polars_lazy/frame/mod.rs
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 1624 1625 1626 1627 1628 1629 1630 1631 1632 1633 1634 1635 1636 1637 1638 1639 1640 1641 1642 1643 1644 1645 1646 1647 1648 1649 1650 1651 1652 1653 1654 1655 1656 1657 1658 1659 1660 1661 1662 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1693 1694 1695 1696 1697 1698 1699 1700 1701 1702 1703 1704 1705 1706 1707 1708 1709 1710 1711 1712 1713 1714 1715 1716 1717 1718 1719 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731 1732 1733 1734 1735 1736 1737 1738 1739 1740 1741 1742 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1755 1756 1757 1758 1759 1760 1761 1762 1763 1764 1765 1766 1767 1768 1769 1770 1771 1772 1773 1774 1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797 1798 1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1905 1906 1907 1908 1909 1910 1911 1912 1913 1914 1915 1916 1917 1918 1919 1920 1921 1922 1923 1924 1925 1926 1927 1928 1929 1930 1931 1932 1933 1934 1935 1936 1937 1938 1939 1940 1941 1942 1943 1944 1945 1946 1947 1948 1949 1950 1951 1952 1953 1954 1955 1956 1957 1958 1959 1960 1961 1962 1963 1964 1965 1966 1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2081 2082 2083 2084 2085 2086 2087 2088 2089 2090 2091 2092 2093 2094 2095 2096 2097 2098 2099 2100 2101 2102 2103 2104 2105 2106 2107 2108 2109 2110 2111 2112 2113 2114 2115 2116 2117 2118 2119 2120 2121 2122 2123 2124 2125 2126 2127 2128 2129 2130 2131 2132 2133 2134 2135 2136 2137 2138 2139 2140 2141 2142 2143 2144 2145 2146 2147 2148 2149 2150 2151 2152 2153 2154 2155 2156 2157 2158 2159 2160 2161 2162 2163 2164 2165 2166 2167 2168 2169 2170 2171 2172 2173 2174 2175 2176 2177 2178 2179 2180 2181 2182 2183 2184 2185 2186 2187 2188 2189 2190 2191 2192 2193 2194 2195 2196 2197 2198 2199 2200 2201 2202 2203 2204 2205 2206 2207 2208 2209 2210 2211 2212 2213 2214 2215 2216 2217 2218 2219 2220 2221 2222 2223 2224 2225 2226 2227 2228 2229 2230 2231 2232 2233 2234 2235 2236 2237 2238 2239 2240 2241 2242 2243 2244 2245 2246 2247 2248 2249 2250 2251 2252 2253 2254
//! Lazy variant of a [DataFrame].
#[cfg(feature = "python")]
mod python;
mod cached_arenas;
mod err;
#[cfg(not(target_arch = "wasm32"))]
mod exitable;
#[cfg(feature = "pivot")]
pub mod pivot;
#[cfg(any(
feature = "parquet",
feature = "ipc",
feature = "csv",
feature = "json"
))]
use std::path::Path;
use std::sync::{Arc, Mutex};
pub use anonymous_scan::*;
#[cfg(feature = "csv")]
pub use csv::*;
#[cfg(not(target_arch = "wasm32"))]
pub use exitable::*;
pub use file_list_reader::*;
#[cfg(feature = "ipc")]
pub use ipc::*;
#[cfg(feature = "json")]
pub use ndjson::*;
#[cfg(feature = "parquet")]
pub use parquet::*;
use polars_core::prelude::*;
use polars_expr::{create_physical_expr, ExpressionConversionState};
use polars_io::RowIndex;
use polars_mem_engine::{create_physical_plan, Executor};
use polars_ops::frame::JoinCoalesce;
#[cfg(feature = "is_between")]
use polars_ops::prelude::ClosedInterval;
pub use polars_plan::frame::{AllowedOptimizations, OptFlags};
use polars_plan::global::FETCH_ROWS;
use polars_utils::pl_str::PlSmallStr;
use crate::frame::cached_arenas::CachedArena;
#[cfg(feature = "streaming")]
use crate::physical_plan::streaming::insert_streaming_nodes;
use crate::prelude::*;
pub trait IntoLazy {
fn lazy(self) -> LazyFrame;
}
impl IntoLazy for DataFrame {
/// Convert the `DataFrame` into a `LazyFrame`
fn lazy(self) -> LazyFrame {
let lp = DslBuilder::from_existing_df(self).build();
LazyFrame {
logical_plan: lp,
opt_state: Default::default(),
cached_arena: Default::default(),
}
}
}
impl IntoLazy for LazyFrame {
fn lazy(self) -> LazyFrame {
self
}
}
/// Lazy abstraction over an eager `DataFrame`.
///
/// It really is an abstraction over a logical plan. The methods of this struct will incrementally
/// modify a logical plan until output is requested (via [`collect`](crate::frame::LazyFrame::collect)).
#[derive(Clone, Default)]
#[must_use]
pub struct LazyFrame {
pub logical_plan: DslPlan,
pub(crate) opt_state: OptFlags,
pub(crate) cached_arena: Arc<Mutex<Option<CachedArena>>>,
}
impl From<DslPlan> for LazyFrame {
fn from(plan: DslPlan) -> Self {
Self {
logical_plan: plan,
opt_state: OptFlags::default() | OptFlags::FILE_CACHING,
cached_arena: Default::default(),
}
}
}
impl LazyFrame {
pub(crate) fn from_inner(
logical_plan: DslPlan,
opt_state: OptFlags,
cached_arena: Arc<Mutex<Option<CachedArena>>>,
) -> Self {
Self {
logical_plan,
opt_state,
cached_arena,
}
}
pub(crate) fn get_plan_builder(self) -> DslBuilder {
DslBuilder::from(self.logical_plan)
}
fn get_opt_state(&self) -> OptFlags {
self.opt_state
}
fn from_logical_plan(logical_plan: DslPlan, opt_state: OptFlags) -> Self {
LazyFrame {
logical_plan,
opt_state,
cached_arena: Default::default(),
}
}
/// Get current optimizations.
pub fn get_current_optimizations(&self) -> OptFlags {
self.opt_state
}
/// Set allowed optimizations.
pub fn with_optimizations(mut self, opt_state: OptFlags) -> Self {
self.opt_state = opt_state;
self
}
/// Turn off all optimizations.
pub fn without_optimizations(self) -> Self {
self.with_optimizations(OptFlags::from_bits_truncate(0) | OptFlags::TYPE_COERCION)
}
/// Toggle projection pushdown optimization.
pub fn with_projection_pushdown(mut self, toggle: bool) -> Self {
self.opt_state.set(OptFlags::PROJECTION_PUSHDOWN, toggle);
self
}
/// Toggle cluster with columns optimization.
pub fn with_cluster_with_columns(mut self, toggle: bool) -> Self {
self.opt_state.set(OptFlags::CLUSTER_WITH_COLUMNS, toggle);
self
}
/// Toggle collapse joins optimization.
pub fn with_collapse_joins(mut self, toggle: bool) -> Self {
self.opt_state.set(OptFlags::COLLAPSE_JOINS, toggle);
self
}
/// Toggle predicate pushdown optimization.
pub fn with_predicate_pushdown(mut self, toggle: bool) -> Self {
self.opt_state.set(OptFlags::PREDICATE_PUSHDOWN, toggle);
self
}
/// Toggle type coercion optimization.
pub fn with_type_coercion(mut self, toggle: bool) -> Self {
self.opt_state.set(OptFlags::TYPE_COERCION, toggle);
self
}
/// Toggle expression simplification optimization on or off.
pub fn with_simplify_expr(mut self, toggle: bool) -> Self {
self.opt_state.set(OptFlags::SIMPLIFY_EXPR, toggle);
self
}
/// Toggle common subplan elimination optimization on or off
#[cfg(feature = "cse")]
pub fn with_comm_subplan_elim(mut self, toggle: bool) -> Self {
self.opt_state.set(OptFlags::COMM_SUBPLAN_ELIM, toggle);
self
}
/// Toggle common subexpression elimination optimization on or off
#[cfg(feature = "cse")]
pub fn with_comm_subexpr_elim(mut self, toggle: bool) -> Self {
self.opt_state.set(OptFlags::COMM_SUBEXPR_ELIM, toggle);
self
}
/// Toggle slice pushdown optimization.
pub fn with_slice_pushdown(mut self, toggle: bool) -> Self {
self.opt_state.set(OptFlags::SLICE_PUSHDOWN, toggle);
self
}
/// Run nodes that are capably of doing so on the streaming engine.
#[cfg(feature = "streaming")]
pub fn with_streaming(mut self, toggle: bool) -> Self {
self.opt_state.set(OptFlags::STREAMING, toggle);
self
}
#[cfg(feature = "new_streaming")]
pub fn with_new_streaming(mut self, toggle: bool) -> Self {
self.opt_state.set(OptFlags::NEW_STREAMING, toggle);
self
}
/// Try to estimate the number of rows so that joins can determine which side to keep in memory.
pub fn with_row_estimate(mut self, toggle: bool) -> Self {
self.opt_state.set(OptFlags::ROW_ESTIMATE, toggle);
self
}
/// Run every node eagerly. This turns off multi-node optimizations.
pub fn _with_eager(mut self, toggle: bool) -> Self {
self.opt_state.set(OptFlags::EAGER, toggle);
self
}
/// Return a String describing the naive (un-optimized) logical plan.
pub fn describe_plan(&self) -> PolarsResult<String> {
Ok(self.clone().to_alp()?.describe())
}
/// Return a String describing the naive (un-optimized) logical plan in tree format.
pub fn describe_plan_tree(&self) -> PolarsResult<String> {
Ok(self.clone().to_alp()?.describe_tree_format())
}
// @NOTE: this is used because we want to set the `enable_fmt` flag of `optimize_with_scratch`
// to `true` for describe.
fn _describe_to_alp_optimized(mut self) -> PolarsResult<IRPlan> {
let (mut lp_arena, mut expr_arena) = self.get_arenas();
let node = self.optimize_with_scratch(&mut lp_arena, &mut expr_arena, &mut vec![], true)?;
Ok(IRPlan::new(node, lp_arena, expr_arena))
}
/// Return a String describing the optimized logical plan.
///
/// Returns `Err` if optimizing the logical plan fails.
pub fn describe_optimized_plan(&self) -> PolarsResult<String> {
Ok(self.clone()._describe_to_alp_optimized()?.describe())
}
/// Return a String describing the optimized logical plan in tree format.
///
/// Returns `Err` if optimizing the logical plan fails.
pub fn describe_optimized_plan_tree(&self) -> PolarsResult<String> {
Ok(self
.clone()
._describe_to_alp_optimized()?
.describe_tree_format())
}
/// Return a String describing the logical plan.
///
/// If `optimized` is `true`, explains the optimized plan. If `optimized` is `false`,
/// explains the naive, un-optimized plan.
pub fn explain(&self, optimized: bool) -> PolarsResult<String> {
if optimized {
self.describe_optimized_plan()
} else {
self.describe_plan()
}
}
/// Add a sort operation to the logical plan.
///
/// Sorts the LazyFrame by the column name specified using the provided options.
///
/// # Example
///
/// Sort DataFrame by 'sepal_width' column:
/// ```rust
/// # use polars_core::prelude::*;
/// # use polars_lazy::prelude::*;
/// fn sort_by_a(df: DataFrame) -> LazyFrame {
/// df.lazy().sort(["sepal_width"], Default::default())
/// }
/// ```
/// Sort by a single column with specific order:
/// ```
/// # use polars_core::prelude::*;
/// # use polars_lazy::prelude::*;
/// fn sort_with_specific_order(df: DataFrame, descending: bool) -> LazyFrame {
/// df.lazy().sort(
/// ["sepal_width"],
/// SortMultipleOptions::new()
/// .with_order_descending(descending)
/// )
/// }
/// ```
/// Sort by multiple columns with specifying order for each column:
/// ```
/// # use polars_core::prelude::*;
/// # use polars_lazy::prelude::*;
/// fn sort_by_multiple_columns_with_specific_order(df: DataFrame) -> LazyFrame {
/// df.lazy().sort(
/// ["sepal_width", "sepal_length"],
/// SortMultipleOptions::new()
/// .with_order_descending_multi([false, true])
/// )
/// }
/// ```
/// See [`SortMultipleOptions`] for more options.
pub fn sort(self, by: impl IntoVec<PlSmallStr>, sort_options: SortMultipleOptions) -> Self {
let opt_state = self.get_opt_state();
let lp = self
.get_plan_builder()
.sort(by.into_vec().into_iter().map(col).collect(), sort_options)
.build();
Self::from_logical_plan(lp, opt_state)
}
/// Add a sort operation to the logical plan.
///
/// Sorts the LazyFrame by the provided list of expressions, which will be turned into
/// concrete columns before sorting.
///
/// See [`SortMultipleOptions`] for more options.
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
///
/// /// Sort DataFrame by 'sepal_width' column
/// fn example(df: DataFrame) -> LazyFrame {
/// df.lazy()
/// .sort_by_exprs(vec![col("sepal_width")], Default::default())
/// }
/// ```
pub fn sort_by_exprs<E: AsRef<[Expr]>>(
self,
by_exprs: E,
sort_options: SortMultipleOptions,
) -> Self {
let by_exprs = by_exprs.as_ref().to_vec();
if by_exprs.is_empty() {
self
} else {
let opt_state = self.get_opt_state();
let lp = self.get_plan_builder().sort(by_exprs, sort_options).build();
Self::from_logical_plan(lp, opt_state)
}
}
pub fn top_k<E: AsRef<[Expr]>>(
self,
k: IdxSize,
by_exprs: E,
sort_options: SortMultipleOptions,
) -> Self {
// this will optimize to top-k
self.sort_by_exprs(
by_exprs,
sort_options.with_order_reversed().with_nulls_last(true),
)
.slice(0, k)
}
pub fn bottom_k<E: AsRef<[Expr]>>(
self,
k: IdxSize,
by_exprs: E,
sort_options: SortMultipleOptions,
) -> Self {
// this will optimize to bottom-k
self.sort_by_exprs(by_exprs, sort_options.with_nulls_last(true))
.slice(0, k)
}
/// Reverse the `DataFrame` from top to bottom.
///
/// Row `i` becomes row `number_of_rows - i - 1`.
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
///
/// fn example(df: DataFrame) -> LazyFrame {
/// df.lazy()
/// .reverse()
/// }
/// ```
pub fn reverse(self) -> Self {
self.select(vec![col(PlSmallStr::from_static("*")).reverse()])
}
/// Rename columns in the DataFrame.
///
/// `existing` and `new` are iterables of the same length containing the old and
/// corresponding new column names. Renaming happens to all `existing` columns
/// simultaneously, not iteratively. If `strict` is true, all columns in `existing`
/// must be present in the `LazyFrame` when `rename` is called; otherwise, only
/// those columns that are actually found will be renamed (others will be ignored).
pub fn rename<I, J, T, S>(self, existing: I, new: J, strict: bool) -> Self
where
I: IntoIterator<Item = T>,
J: IntoIterator<Item = S>,
T: AsRef<str>,
S: AsRef<str>,
{
let iter = existing.into_iter();
let cap = iter.size_hint().0;
let mut existing_vec: Vec<PlSmallStr> = Vec::with_capacity(cap);
let mut new_vec: Vec<PlSmallStr> = Vec::with_capacity(cap);
// TODO! should this error if `existing` and `new` have different lengths?
// Currently, the longer of the two is truncated.
for (existing, new) in iter.zip(new) {
let existing = existing.as_ref();
let new = new.as_ref();
if new != existing {
existing_vec.push(existing.into());
new_vec.push(new.into());
}
}
self.map_private(DslFunction::Rename {
existing: existing_vec.into(),
new: new_vec.into(),
strict,
})
}
/// Removes columns from the DataFrame.
/// Note that it's better to only select the columns you need
/// and let the projection pushdown optimize away the unneeded columns.
///
/// If `strict` is `true`, then any given columns that are not in the schema will
/// give a [`PolarsError::ColumnNotFound`] error while materializing the [`LazyFrame`].
fn _drop<I, T>(self, columns: I, strict: bool) -> Self
where
I: IntoIterator<Item = T>,
T: Into<Selector>,
{
let to_drop = columns.into_iter().map(|c| c.into()).collect();
let opt_state = self.get_opt_state();
let lp = self.get_plan_builder().drop(to_drop, strict).build();
Self::from_logical_plan(lp, opt_state)
}
/// Removes columns from the DataFrame.
/// Note that it's better to only select the columns you need
/// and let the projection pushdown optimize away the unneeded columns.
///
/// Any given columns that are not in the schema will give a [`PolarsError::ColumnNotFound`]
/// error while materializing the [`LazyFrame`].
pub fn drop<I, T>(self, columns: I) -> Self
where
I: IntoIterator<Item = T>,
T: Into<Selector>,
{
self._drop(columns, true)
}
/// Removes columns from the DataFrame.
/// Note that it's better to only select the columns you need
/// and let the projection pushdown optimize away the unneeded columns.
///
/// If a column name does not exist in the schema, it will quietly be ignored.
pub fn drop_no_validate<I, T>(self, columns: I) -> Self
where
I: IntoIterator<Item = T>,
T: Into<Selector>,
{
self._drop(columns, false)
}
/// Shift the values by a given period and fill the parts that will be empty due to this operation
/// with `Nones`.
///
/// See the method on [Series](polars_core::series::SeriesTrait::shift) for more info on the `shift` operation.
pub fn shift<E: Into<Expr>>(self, n: E) -> Self {
self.select(vec![col(PlSmallStr::from_static("*")).shift(n.into())])
}
/// Shift the values by a given period and fill the parts that will be empty due to this operation
/// with the result of the `fill_value` expression.
///
/// See the method on [Series](polars_core::series::SeriesTrait::shift) for more info on the `shift` operation.
pub fn shift_and_fill<E: Into<Expr>, IE: Into<Expr>>(self, n: E, fill_value: IE) -> Self {
self.select(vec![
col(PlSmallStr::from_static("*")).shift_and_fill(n.into(), fill_value.into())
])
}
/// Fill None values in the DataFrame with an expression.
pub fn fill_null<E: Into<Expr>>(self, fill_value: E) -> LazyFrame {
let opt_state = self.get_opt_state();
let lp = self.get_plan_builder().fill_null(fill_value.into()).build();
Self::from_logical_plan(lp, opt_state)
}
/// Fill NaN values in the DataFrame with an expression.
pub fn fill_nan<E: Into<Expr>>(self, fill_value: E) -> LazyFrame {
let opt_state = self.get_opt_state();
let lp = self.get_plan_builder().fill_nan(fill_value.into()).build();
Self::from_logical_plan(lp, opt_state)
}
/// Caches the result into a new LazyFrame.
///
/// This should be used to prevent computations running multiple times.
pub fn cache(self) -> Self {
let opt_state = self.get_opt_state();
let lp = self.get_plan_builder().cache().build();
Self::from_logical_plan(lp, opt_state)
}
/// Cast named frame columns, resulting in a new LazyFrame with updated dtypes
pub fn cast(self, dtypes: PlHashMap<&str, DataType>, strict: bool) -> Self {
let cast_cols: Vec<Expr> = dtypes
.into_iter()
.map(|(name, dt)| {
let name = PlSmallStr::from_str(name);
if strict {
col(name).strict_cast(dt)
} else {
col(name).cast(dt)
}
})
.collect();
if cast_cols.is_empty() {
self.clone()
} else {
self.with_columns(cast_cols)
}
}
/// Cast all frame columns to the given dtype, resulting in a new LazyFrame
pub fn cast_all(self, dtype: DataType, strict: bool) -> Self {
self.with_columns(vec![if strict {
col(PlSmallStr::from_static("*")).strict_cast(dtype)
} else {
col(PlSmallStr::from_static("*")).cast(dtype)
}])
}
/// Fetch is like a collect operation, but it overwrites the number of rows read by every scan
/// operation. This is a utility that helps debug a query on a smaller number of rows.
///
/// Note that the fetch does not guarantee the final number of rows in the DataFrame.
/// Filter, join operations and a lower number of rows available in the scanned file influence
/// the final number of rows.
pub fn fetch(self, n_rows: usize) -> PolarsResult<DataFrame> {
FETCH_ROWS.with(|fetch_rows| fetch_rows.set(Some(n_rows)));
let res = self.collect();
FETCH_ROWS.with(|fetch_rows| fetch_rows.set(None));
res
}
pub fn optimize(
self,
lp_arena: &mut Arena<IR>,
expr_arena: &mut Arena<AExpr>,
) -> PolarsResult<Node> {
self.optimize_with_scratch(lp_arena, expr_arena, &mut vec![], false)
}
pub fn to_alp_optimized(mut self) -> PolarsResult<IRPlan> {
let (mut lp_arena, mut expr_arena) = self.get_arenas();
let node =
self.optimize_with_scratch(&mut lp_arena, &mut expr_arena, &mut vec![], false)?;
Ok(IRPlan::new(node, lp_arena, expr_arena))
}
pub fn to_alp(mut self) -> PolarsResult<IRPlan> {
let (mut lp_arena, mut expr_arena) = self.get_arenas();
let node = to_alp(
self.logical_plan,
&mut expr_arena,
&mut lp_arena,
&mut self.opt_state,
)?;
let plan = IRPlan::new(node, lp_arena, expr_arena);
Ok(plan)
}
pub(crate) fn optimize_with_scratch(
self,
lp_arena: &mut Arena<IR>,
expr_arena: &mut Arena<AExpr>,
scratch: &mut Vec<Node>,
enable_fmt: bool,
) -> PolarsResult<Node> {
#[allow(unused_mut)]
let mut opt_state = self.opt_state;
let streaming = self.opt_state.contains(OptFlags::STREAMING);
let new_streaming = self.opt_state.contains(OptFlags::NEW_STREAMING);
#[cfg(feature = "cse")]
if streaming && !new_streaming {
opt_state &= !OptFlags::COMM_SUBPLAN_ELIM;
}
// The new streaming engine can't deal with the way the common
// subexpression elimination adds length-incorrect with_columns.
#[cfg(feature = "cse")]
if new_streaming {
opt_state &= !OptFlags::COMM_SUBEXPR_ELIM;
}
let lp_top = optimize(
self.logical_plan,
opt_state,
lp_arena,
expr_arena,
scratch,
Some(&|expr, expr_arena, schema| {
let phys_expr = create_physical_expr(
expr,
Context::Default,
expr_arena,
schema,
&mut ExpressionConversionState::new(true, 0),
)
.ok()?;
let io_expr = phys_expr_to_io_expr(phys_expr);
Some(io_expr)
}),
)?;
if streaming {
#[cfg(feature = "streaming")]
{
insert_streaming_nodes(
lp_top,
lp_arena,
expr_arena,
scratch,
enable_fmt,
true,
opt_state.contains(OptFlags::ROW_ESTIMATE),
)?;
}
#[cfg(not(feature = "streaming"))]
{
_ = enable_fmt;
panic!("activate feature 'streaming'")
}
}
Ok(lp_top)
}
fn prepare_collect_post_opt<P>(
mut self,
check_sink: bool,
post_opt: P,
) -> PolarsResult<(ExecutionState, Box<dyn Executor>, bool)>
where
P: Fn(Node, &mut Arena<IR>, &mut Arena<AExpr>) -> PolarsResult<()>,
{
let (mut lp_arena, mut expr_arena) = self.get_arenas();
let mut scratch = vec![];
let lp_top =
self.optimize_with_scratch(&mut lp_arena, &mut expr_arena, &mut scratch, false)?;
post_opt(lp_top, &mut lp_arena, &mut expr_arena)?;
// sink should be replaced
let no_file_sink = if check_sink {
!matches!(lp_arena.get(lp_top), IR::Sink { .. })
} else {
true
};
let physical_plan = create_physical_plan(lp_top, &mut lp_arena, &expr_arena)?;
let state = ExecutionState::new();
Ok((state, physical_plan, no_file_sink))
}
// post_opt: A function that is called after optimization. This can be used to modify the IR jit.
pub fn _collect_post_opt<P>(self, post_opt: P) -> PolarsResult<DataFrame>
where
P: Fn(Node, &mut Arena<IR>, &mut Arena<AExpr>) -> PolarsResult<()>,
{
let (mut state, mut physical_plan, _) = self.prepare_collect_post_opt(false, post_opt)?;
physical_plan.execute(&mut state)
}
#[allow(unused_mut)]
fn prepare_collect(
self,
check_sink: bool,
) -> PolarsResult<(ExecutionState, Box<dyn Executor>, bool)> {
self.prepare_collect_post_opt(check_sink, |_, _, _| Ok(()))
}
/// Execute all the lazy operations and collect them into a [`DataFrame`].
///
/// The query is optimized prior to execution.
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
///
/// fn example(df: DataFrame) -> PolarsResult<DataFrame> {
/// df.lazy()
/// .group_by([col("foo")])
/// .agg([col("bar").sum(), col("ham").mean().alias("avg_ham")])
/// .collect()
/// }
/// ```
pub fn collect(self) -> PolarsResult<DataFrame> {
#[cfg(feature = "new_streaming")]
{
let mut slf = self;
if let Some(df) = slf.try_new_streaming_if_requested(SinkType::Memory) {
return Ok(df?.unwrap());
}
let mut alp_plan = slf.to_alp_optimized()?;
let mut physical_plan = create_physical_plan(
alp_plan.lp_top,
&mut alp_plan.lp_arena,
&alp_plan.expr_arena,
)?;
let mut state = ExecutionState::new();
physical_plan.execute(&mut state)
}
#[cfg(not(feature = "new_streaming"))]
self._collect_post_opt(|_, _, _| Ok(()))
}
/// Profile a LazyFrame.
///
/// This will run the query and return a tuple
/// containing the materialized DataFrame and a DataFrame that contains profiling information
/// of each node that is executed.
///
/// The units of the timings are microseconds.
pub fn profile(self) -> PolarsResult<(DataFrame, DataFrame)> {
let (mut state, mut physical_plan, _) = self.prepare_collect(false)?;
state.time_nodes();
let out = physical_plan.execute(&mut state)?;
let timer_df = state.finish_timer()?;
Ok((out, timer_df))
}
/// Stream a query result into a parquet file. This is useful if the final result doesn't fit
/// into memory. This methods will return an error if the query cannot be completely done in a
/// streaming fashion.
#[cfg(feature = "parquet")]
pub fn sink_parquet(
self,
path: impl AsRef<Path>,
options: ParquetWriteOptions,
) -> PolarsResult<()> {
self.sink(
SinkType::File {
path: Arc::new(path.as_ref().to_path_buf()),
file_type: FileType::Parquet(options),
},
"collect().write_parquet()",
)
}
/// Stream a query result into a parquet file on an ObjectStore-compatible cloud service. This is useful if the final result doesn't fit
/// into memory, and where you do not want to write to a local file but to a location in the cloud.
/// This method will return an error if the query cannot be completely done in a
/// streaming fashion.
#[cfg(all(feature = "cloud_write", feature = "parquet"))]
pub fn sink_parquet_cloud(
self,
uri: String,
cloud_options: Option<polars_io::cloud::CloudOptions>,
parquet_options: ParquetWriteOptions,
) -> PolarsResult<()> {
self.sink(
SinkType::Cloud {
uri: Arc::new(uri),
cloud_options,
file_type: FileType::Parquet(parquet_options),
},
"collect().write_parquet()",
)
}
/// Stream a query result into an ipc/arrow file. This is useful if the final result doesn't fit
/// into memory. This methods will return an error if the query cannot be completely done in a
/// streaming fashion.
#[cfg(feature = "ipc")]
pub fn sink_ipc(self, path: impl AsRef<Path>, options: IpcWriterOptions) -> PolarsResult<()> {
self.sink(
SinkType::File {
path: Arc::new(path.as_ref().to_path_buf()),
file_type: FileType::Ipc(options),
},
"collect().write_ipc()",
)
}
/// Stream a query result into an ipc/arrow file on an ObjectStore-compatible cloud service.
/// This is useful if the final result doesn't fit
/// into memory, and where you do not want to write to a local file but to a location in the cloud.
/// This method will return an error if the query cannot be completely done in a
/// streaming fashion.
#[cfg(all(feature = "cloud_write", feature = "ipc"))]
pub fn sink_ipc_cloud(
mut self,
uri: String,
cloud_options: Option<polars_io::cloud::CloudOptions>,
ipc_options: IpcWriterOptions,
) -> PolarsResult<()> {
self.opt_state |= OptFlags::STREAMING;
self.logical_plan = DslPlan::Sink {
input: Arc::new(self.logical_plan),
payload: SinkType::Cloud {
uri: Arc::new(uri),
cloud_options,
file_type: FileType::Ipc(ipc_options),
},
};
let (mut state, mut physical_plan, is_streaming) = self.prepare_collect(true)?;
polars_ensure!(
is_streaming,
ComputeError: "cannot run the whole query in a streaming order; \
use `collect().write_ipc()` instead"
);
let _ = physical_plan.execute(&mut state)?;
Ok(())
}
/// Stream a query result into an csv file. This is useful if the final result doesn't fit
/// into memory. This methods will return an error if the query cannot be completely done in a
/// streaming fashion.
#[cfg(feature = "csv")]
pub fn sink_csv(self, path: impl AsRef<Path>, options: CsvWriterOptions) -> PolarsResult<()> {
self.sink(
SinkType::File {
path: Arc::new(path.as_ref().to_path_buf()),
file_type: FileType::Csv(options),
},
"collect().write_csv()",
)
}
/// Stream a query result into a json file. This is useful if the final result doesn't fit
/// into memory. This methods will return an error if the query cannot be completely done in a
/// streaming fashion.
#[cfg(feature = "json")]
pub fn sink_json(self, path: impl AsRef<Path>, options: JsonWriterOptions) -> PolarsResult<()> {
self.sink(
SinkType::File {
path: Arc::new(path.as_ref().to_path_buf()),
file_type: FileType::Json(options),
},
"collect().write_ndjson()` or `collect().write_json()",
)
}
#[cfg(feature = "new_streaming")]
pub fn try_new_streaming_if_requested(
&mut self,
payload: SinkType,
) -> Option<PolarsResult<Option<DataFrame>>> {
let auto_new_streaming = std::env::var("POLARS_AUTO_NEW_STREAMING").as_deref() == Ok("1");
let force_new_streaming = std::env::var("POLARS_FORCE_NEW_STREAMING").as_deref() == Ok("1");
if self.opt_state.contains(OptFlags::NEW_STREAMING)
|| auto_new_streaming
|| force_new_streaming
{
// Try to run using the new streaming engine, falling back
// if it fails in a todo!() error if auto_new_streaming is set.
let mut new_stream_lazy = self.clone();
new_stream_lazy.opt_state |= OptFlags::NEW_STREAMING;
new_stream_lazy.opt_state &= !OptFlags::STREAMING;
let mut alp_plan = match new_stream_lazy.to_alp_optimized() {
Ok(v) => v,
Err(e) => return Some(Err(e)),
};
let stream_lp_top = alp_plan.lp_arena.add(IR::Sink {
input: alp_plan.lp_top,
payload,
});
let f = || {
polars_stream::run_query(stream_lp_top, alp_plan.lp_arena, &mut alp_plan.expr_arena)
};
match std::panic::catch_unwind(std::panic::AssertUnwindSafe(f)) {
Ok(v) => return Some(v),
Err(e) => {
// Fallback to normal engine if error is due to not being implemented
// and auto_new_streaming is set, otherwise propagate error.
if !force_new_streaming
&& auto_new_streaming
&& e.downcast_ref::<&str>()
.map(|s| s.starts_with("not yet implemented"))
.unwrap_or(false)
{
if polars_core::config::verbose() {
eprintln!("caught unimplemented error in new streaming engine, falling back to normal engine");
}
} else {
std::panic::resume_unwind(e);
}
},
}
}
None
}
#[cfg(any(
feature = "ipc",
feature = "parquet",
feature = "cloud_write",
feature = "csv",
feature = "json",
))]
fn sink(mut self, payload: SinkType, msg_alternative: &str) -> Result<(), PolarsError> {
#[cfg(feature = "new_streaming")]
{
if self
.try_new_streaming_if_requested(payload.clone())
.is_some()
{
return Ok(());
}
}
self.logical_plan = DslPlan::Sink {
input: Arc::new(self.logical_plan),
payload,
};
self.opt_state |= OptFlags::STREAMING;
let (mut state, mut physical_plan, is_streaming) = self.prepare_collect(true)?;
polars_ensure!(
is_streaming,
ComputeError: format!("cannot run the whole query in a streaming order; \
use `{msg_alternative}` instead", msg_alternative=msg_alternative)
);
let _ = physical_plan.execute(&mut state)?;
Ok(())
}
/// Filter by some predicate expression.
///
/// The expression must yield boolean values.
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
///
/// fn example(df: DataFrame) -> LazyFrame {
/// df.lazy()
/// .filter(col("sepal_width").is_not_null())
/// .select([col("sepal_width"), col("sepal_length")])
/// }
/// ```
pub fn filter(self, predicate: Expr) -> Self {
let opt_state = self.get_opt_state();
let lp = self.get_plan_builder().filter(predicate).build();
Self::from_logical_plan(lp, opt_state)
}
/// Select (and optionally rename, with [`alias`](crate::dsl::Expr::alias)) columns from the query.
///
/// Columns can be selected with [`col`];
/// If you want to select all columns use `col(PlSmallStr::from_static("*"))`.
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
///
/// /// This function selects column "foo" and column "bar".
/// /// Column "bar" is renamed to "ham".
/// fn example(df: DataFrame) -> LazyFrame {
/// df.lazy()
/// .select([col("foo"),
/// col("bar").alias("ham")])
/// }
///
/// /// This function selects all columns except "foo"
/// fn exclude_a_column(df: DataFrame) -> LazyFrame {
/// df.lazy()
/// .select([col(PlSmallStr::from_static("*")).exclude(["foo"])])
/// }
/// ```
pub fn select<E: AsRef<[Expr]>>(self, exprs: E) -> Self {
let exprs = exprs.as_ref().to_vec();
self.select_impl(
exprs,
ProjectionOptions {
run_parallel: true,
duplicate_check: true,
should_broadcast: true,
},
)
}
pub fn select_seq<E: AsRef<[Expr]>>(self, exprs: E) -> Self {
let exprs = exprs.as_ref().to_vec();
self.select_impl(
exprs,
ProjectionOptions {
run_parallel: false,
duplicate_check: true,
should_broadcast: true,
},
)
}
fn select_impl(self, exprs: Vec<Expr>, options: ProjectionOptions) -> Self {
let opt_state = self.get_opt_state();
let lp = self.get_plan_builder().project(exprs, options).build();
Self::from_logical_plan(lp, opt_state)
}
/// Performs a "group-by" on a `LazyFrame`, producing a [`LazyGroupBy`], which can subsequently be aggregated.
///
/// Takes a list of expressions to group on.
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
/// use arrow::legacy::prelude::QuantileMethod;
///
/// fn example(df: DataFrame) -> LazyFrame {
/// df.lazy()
/// .group_by([col("date")])
/// .agg([
/// col("rain").min().alias("min_rain"),
/// col("rain").sum().alias("sum_rain"),
/// col("rain").quantile(lit(0.5), QuantileMethod::Nearest).alias("median_rain"),
/// ])
/// }
/// ```
pub fn group_by<E: AsRef<[IE]>, IE: Into<Expr> + Clone>(self, by: E) -> LazyGroupBy {
let keys = by
.as_ref()
.iter()
.map(|e| e.clone().into())
.collect::<Vec<_>>();
let opt_state = self.get_opt_state();
#[cfg(feature = "dynamic_group_by")]
{
LazyGroupBy {
logical_plan: self.logical_plan,
opt_state,
keys,
maintain_order: false,
dynamic_options: None,
rolling_options: None,
}
}
#[cfg(not(feature = "dynamic_group_by"))]
{
LazyGroupBy {
logical_plan: self.logical_plan,
opt_state,
keys,
maintain_order: false,
}
}
}
/// Create rolling groups based on a time column.
///
/// Also works for index values of type UInt32, UInt64, Int32, or Int64.
///
/// Different from a [`group_by_dynamic`][`Self::group_by_dynamic`], the windows are now determined by the
/// individual values and are not of constant intervals. For constant intervals use
/// *group_by_dynamic*
#[cfg(feature = "dynamic_group_by")]
pub fn rolling<E: AsRef<[Expr]>>(
mut self,
index_column: Expr,
group_by: E,
mut options: RollingGroupOptions,
) -> LazyGroupBy {
if let Expr::Column(name) = index_column {
options.index_column = name;
} else {
let output_field = index_column
.to_field(&self.collect_schema().unwrap(), Context::Default)
.unwrap();
return self.with_column(index_column).rolling(
Expr::Column(output_field.name().clone()),
group_by,
options,
);
}
let opt_state = self.get_opt_state();
LazyGroupBy {
logical_plan: self.logical_plan,
opt_state,
keys: group_by.as_ref().to_vec(),
maintain_order: true,
dynamic_options: None,
rolling_options: Some(options),
}
}
/// Group based on a time value (or index value of type Int32, Int64).
///
/// Time windows are calculated and rows are assigned to windows. Different from a
/// normal group_by is that a row can be member of multiple groups. The time/index
/// window could be seen as a rolling window, with a window size determined by
/// dates/times/values instead of slots in the DataFrame.
///
/// A window is defined by:
///
/// - every: interval of the window
/// - period: length of the window
/// - offset: offset of the window
///
/// The `group_by` argument should be empty `[]` if you don't want to combine this
/// with a ordinary group_by on these keys.
#[cfg(feature = "dynamic_group_by")]
pub fn group_by_dynamic<E: AsRef<[Expr]>>(
mut self,
index_column: Expr,
group_by: E,
mut options: DynamicGroupOptions,
) -> LazyGroupBy {
if let Expr::Column(name) = index_column {
options.index_column = name;
} else {
let output_field = index_column
.to_field(&self.collect_schema().unwrap(), Context::Default)
.unwrap();
return self.with_column(index_column).group_by_dynamic(
Expr::Column(output_field.name().clone()),
group_by,
options,
);
}
let opt_state = self.get_opt_state();
LazyGroupBy {
logical_plan: self.logical_plan,
opt_state,
keys: group_by.as_ref().to_vec(),
maintain_order: true,
dynamic_options: Some(options),
rolling_options: None,
}
}
/// Similar to [`group_by`][`Self::group_by`], but order of the DataFrame is maintained.
pub fn group_by_stable<E: AsRef<[IE]>, IE: Into<Expr> + Clone>(self, by: E) -> LazyGroupBy {
let keys = by
.as_ref()
.iter()
.map(|e| e.clone().into())
.collect::<Vec<_>>();
let opt_state = self.get_opt_state();
#[cfg(feature = "dynamic_group_by")]
{
LazyGroupBy {
logical_plan: self.logical_plan,
opt_state,
keys,
maintain_order: true,
dynamic_options: None,
rolling_options: None,
}
}
#[cfg(not(feature = "dynamic_group_by"))]
{
LazyGroupBy {
logical_plan: self.logical_plan,
opt_state,
keys,
maintain_order: true,
}
}
}
/// Left anti join this query with another lazy query.
///
/// Matches on the values of the expressions `left_on` and `right_on`. For more
/// flexible join logic, see [`join`](LazyFrame::join) or
/// [`join_builder`](LazyFrame::join_builder).
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
/// fn anti_join_dataframes(ldf: LazyFrame, other: LazyFrame) -> LazyFrame {
/// ldf
/// .anti_join(other, col("foo"), col("bar").cast(DataType::String))
/// }
/// ```
#[cfg(feature = "semi_anti_join")]
pub fn anti_join<E: Into<Expr>>(self, other: LazyFrame, left_on: E, right_on: E) -> LazyFrame {
self.join(
other,
[left_on.into()],
[right_on.into()],
JoinArgs::new(JoinType::Anti),
)
}
/// Creates the Cartesian product from both frames, preserving the order of the left keys.
#[cfg(feature = "cross_join")]
pub fn cross_join(self, other: LazyFrame, suffix: Option<PlSmallStr>) -> LazyFrame {
self.join(
other,
vec![],
vec![],
JoinArgs::new(JoinType::Cross).with_suffix(suffix),
)
}
/// Left outer join this query with another lazy query.
///
/// Matches on the values of the expressions `left_on` and `right_on`. For more
/// flexible join logic, see [`join`](LazyFrame::join) or
/// [`join_builder`](LazyFrame::join_builder).
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
/// fn left_join_dataframes(ldf: LazyFrame, other: LazyFrame) -> LazyFrame {
/// ldf
/// .left_join(other, col("foo"), col("bar"))
/// }
/// ```
pub fn left_join<E: Into<Expr>>(self, other: LazyFrame, left_on: E, right_on: E) -> LazyFrame {
self.join(
other,
[left_on.into()],
[right_on.into()],
JoinArgs::new(JoinType::Left),
)
}
/// Inner join this query with another lazy query.
///
/// Matches on the values of the expressions `left_on` and `right_on`. For more
/// flexible join logic, see [`join`](LazyFrame::join) or
/// [`join_builder`](LazyFrame::join_builder).
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
/// fn inner_join_dataframes(ldf: LazyFrame, other: LazyFrame) -> LazyFrame {
/// ldf
/// .inner_join(other, col("foo"), col("bar").cast(DataType::String))
/// }
/// ```
pub fn inner_join<E: Into<Expr>>(self, other: LazyFrame, left_on: E, right_on: E) -> LazyFrame {
self.join(
other,
[left_on.into()],
[right_on.into()],
JoinArgs::new(JoinType::Inner),
)
}
/// Full outer join this query with another lazy query.
///
/// Matches on the values of the expressions `left_on` and `right_on`. For more
/// flexible join logic, see [`join`](LazyFrame::join) or
/// [`join_builder`](LazyFrame::join_builder).
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
/// fn full_join_dataframes(ldf: LazyFrame, other: LazyFrame) -> LazyFrame {
/// ldf
/// .full_join(other, col("foo"), col("bar"))
/// }
/// ```
pub fn full_join<E: Into<Expr>>(self, other: LazyFrame, left_on: E, right_on: E) -> LazyFrame {
self.join(
other,
[left_on.into()],
[right_on.into()],
JoinArgs::new(JoinType::Full),
)
}
/// Left semi join this query with another lazy query.
///
/// Matches on the values of the expressions `left_on` and `right_on`. For more
/// flexible join logic, see [`join`](LazyFrame::join) or
/// [`join_builder`](LazyFrame::join_builder).
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
/// fn semi_join_dataframes(ldf: LazyFrame, other: LazyFrame) -> LazyFrame {
/// ldf
/// .semi_join(other, col("foo"), col("bar").cast(DataType::String))
/// }
/// ```
#[cfg(feature = "semi_anti_join")]
pub fn semi_join<E: Into<Expr>>(self, other: LazyFrame, left_on: E, right_on: E) -> LazyFrame {
self.join(
other,
[left_on.into()],
[right_on.into()],
JoinArgs::new(JoinType::Semi),
)
}
/// Generic function to join two LazyFrames.
///
/// `join` can join on multiple columns, given as two list of expressions, and with a
/// [`JoinType`] specified by `how`. Non-joined column names in the right DataFrame
/// that already exist in this DataFrame are suffixed with `"_right"`. For control
/// over how columns are renamed and parallelization options, use
/// [`join_builder`](LazyFrame::join_builder).
///
/// Any provided `args.slice` parameter is not considered, but set by the internal optimizer.
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
///
/// fn example(ldf: LazyFrame, other: LazyFrame) -> LazyFrame {
/// ldf
/// .join(other, [col("foo"), col("bar")], [col("foo"), col("bar")], JoinArgs::new(JoinType::Inner))
/// }
/// ```
pub fn join<E: AsRef<[Expr]>>(
mut self,
other: LazyFrame,
left_on: E,
right_on: E,
args: JoinArgs,
) -> LazyFrame {
// if any of the nodes reads from files we must activate this plan as well.
if other.opt_state.contains(OptFlags::FILE_CACHING) {
self.opt_state |= OptFlags::FILE_CACHING;
}
let left_on = left_on.as_ref().to_vec();
let right_on = right_on.as_ref().to_vec();
let mut builder = self
.join_builder()
.with(other)
.left_on(left_on)
.right_on(right_on)
.how(args.how)
.validate(args.validation)
.coalesce(args.coalesce)
.join_nulls(args.join_nulls);
if let Some(suffix) = args.suffix {
builder = builder.suffix(suffix);
}
// Note: args.slice is set by the optimizer
builder.finish()
}
/// Consume `self` and return a [`JoinBuilder`] to customize a join on this LazyFrame.
///
/// After the `JoinBuilder` has been created and set up, calling
/// [`finish()`](JoinBuilder::finish) on it will give back the `LazyFrame`
/// representing the `join` operation.
pub fn join_builder(self) -> JoinBuilder {
JoinBuilder::new(self)
}
/// Add or replace a column, given as an expression, to a DataFrame.
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
/// fn add_column(df: DataFrame) -> LazyFrame {
/// df.lazy()
/// .with_column(
/// when(col("sepal_length").lt(lit(5.0)))
/// .then(lit(10))
/// .otherwise(lit(1))
/// .alias("new_column_name"),
/// )
/// }
/// ```
pub fn with_column(self, expr: Expr) -> LazyFrame {
let opt_state = self.get_opt_state();
let lp = self
.get_plan_builder()
.with_columns(
vec![expr],
ProjectionOptions {
run_parallel: false,
duplicate_check: true,
should_broadcast: true,
},
)
.build();
Self::from_logical_plan(lp, opt_state)
}
/// Add or replace multiple columns, given as expressions, to a DataFrame.
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
/// fn add_columns(df: DataFrame) -> LazyFrame {
/// df.lazy()
/// .with_columns(
/// vec![lit(10).alias("foo"), lit(100).alias("bar")]
/// )
/// }
/// ```
pub fn with_columns<E: AsRef<[Expr]>>(self, exprs: E) -> LazyFrame {
let exprs = exprs.as_ref().to_vec();
self.with_columns_impl(
exprs,
ProjectionOptions {
run_parallel: true,
duplicate_check: true,
should_broadcast: true,
},
)
}
/// Add or replace multiple columns to a DataFrame, but evaluate them sequentially.
pub fn with_columns_seq<E: AsRef<[Expr]>>(self, exprs: E) -> LazyFrame {
let exprs = exprs.as_ref().to_vec();
self.with_columns_impl(
exprs,
ProjectionOptions {
run_parallel: false,
duplicate_check: true,
should_broadcast: true,
},
)
}
fn with_columns_impl(self, exprs: Vec<Expr>, options: ProjectionOptions) -> LazyFrame {
let opt_state = self.get_opt_state();
let lp = self.get_plan_builder().with_columns(exprs, options).build();
Self::from_logical_plan(lp, opt_state)
}
pub fn with_context<C: AsRef<[LazyFrame]>>(self, contexts: C) -> LazyFrame {
let contexts = contexts
.as_ref()
.iter()
.map(|lf| lf.logical_plan.clone())
.collect();
let opt_state = self.get_opt_state();
let lp = self.get_plan_builder().with_context(contexts).build();
Self::from_logical_plan(lp, opt_state)
}
/// Aggregate all the columns as their maximum values.
///
/// Aggregated columns will have the same names as the original columns.
pub fn max(self) -> Self {
self.map_private(DslFunction::Stats(StatsFunction::Max))
}
/// Aggregate all the columns as their minimum values.
///
/// Aggregated columns will have the same names as the original columns.
pub fn min(self) -> Self {
self.map_private(DslFunction::Stats(StatsFunction::Min))
}
/// Aggregate all the columns as their sum values.
///
/// Aggregated columns will have the same names as the original columns.
///
/// - Boolean columns will sum to a `u32` containing the number of `true`s.
/// - For integer columns, the ordinary checks for overflow are performed:
/// if running in `debug` mode, overflows will panic, whereas in `release` mode overflows will
/// silently wrap.
/// - String columns will sum to None.
pub fn sum(self) -> Self {
self.map_private(DslFunction::Stats(StatsFunction::Sum))
}
/// Aggregate all the columns as their mean values.
///
/// - Boolean and integer columns are converted to `f64` before computing the mean.
/// - String columns will have a mean of None.
pub fn mean(self) -> Self {
self.map_private(DslFunction::Stats(StatsFunction::Mean))
}
/// Aggregate all the columns as their median values.
///
/// - Boolean and integer results are converted to `f64`. However, they are still
/// susceptible to overflow before this conversion occurs.
/// - String columns will sum to None.
pub fn median(self) -> Self {
self.map_private(DslFunction::Stats(StatsFunction::Median))
}
/// Aggregate all the columns as their quantile values.
pub fn quantile(self, quantile: Expr, method: QuantileMethod) -> Self {
self.map_private(DslFunction::Stats(StatsFunction::Quantile {
quantile,
method,
}))
}
/// Aggregate all the columns as their standard deviation values.
///
/// `ddof` is the "Delta Degrees of Freedom"; `N - ddof` will be the denominator when
/// computing the variance, where `N` is the number of rows.
/// > In standard statistical practice, `ddof=1` provides an unbiased estimator of the
/// > variance of a hypothetical infinite population. `ddof=0` provides a maximum
/// > likelihood estimate of the variance for normally distributed variables. The
/// > standard deviation computed in this function is the square root of the estimated
/// > variance, so even with `ddof=1`, it will not be an unbiased estimate of the
/// > standard deviation per se.
///
/// Source: [Numpy](https://numpy.org/doc/stable/reference/generated/numpy.std.html#)
pub fn std(self, ddof: u8) -> Self {
self.map_private(DslFunction::Stats(StatsFunction::Std { ddof }))
}
/// Aggregate all the columns as their variance values.
///
/// `ddof` is the "Delta Degrees of Freedom"; `N - ddof` will be the denominator when
/// computing the variance, where `N` is the number of rows.
/// > In standard statistical practice, `ddof=1` provides an unbiased estimator of the
/// > variance of a hypothetical infinite population. `ddof=0` provides a maximum
/// > likelihood estimate of the variance for normally distributed variables.
///
/// Source: [Numpy](https://numpy.org/doc/stable/reference/generated/numpy.var.html#)
pub fn var(self, ddof: u8) -> Self {
self.map_private(DslFunction::Stats(StatsFunction::Var { ddof }))
}
/// Apply explode operation. [See eager explode](polars_core::frame::DataFrame::explode).
pub fn explode<E: AsRef<[IE]>, IE: Into<Selector> + Clone>(self, columns: E) -> LazyFrame {
self.explode_impl(columns, false)
}
/// Apply explode operation. [See eager explode](polars_core::frame::DataFrame::explode).
fn explode_impl<E: AsRef<[IE]>, IE: Into<Selector> + Clone>(
self,
columns: E,
allow_empty: bool,
) -> LazyFrame {
let columns = columns
.as_ref()
.iter()
.map(|e| e.clone().into())
.collect::<Vec<_>>();
let opt_state = self.get_opt_state();
let lp = self
.get_plan_builder()
.explode(columns, allow_empty)
.build();
Self::from_logical_plan(lp, opt_state)
}
/// Aggregate all the columns as the sum of their null value count.
pub fn null_count(self) -> LazyFrame {
self.select(vec![col(PlSmallStr::from_static("*")).null_count()])
}
/// Drop non-unique rows and maintain the order of kept rows.
///
/// `subset` is an optional `Vec` of column names to consider for uniqueness; if
/// `None`, all columns are considered.
pub fn unique_stable(
self,
subset: Option<Vec<PlSmallStr>>,
keep_strategy: UniqueKeepStrategy,
) -> LazyFrame {
self.unique_stable_generic(subset, keep_strategy)
}
pub fn unique_stable_generic<E, IE>(
self,
subset: Option<E>,
keep_strategy: UniqueKeepStrategy,
) -> LazyFrame
where
E: AsRef<[IE]>,
IE: Into<Selector> + Clone,
{
let subset = subset.map(|s| {
s.as_ref()
.iter()
.map(|e| e.clone().into())
.collect::<Vec<_>>()
});
let opt_state = self.get_opt_state();
let options = DistinctOptionsDSL {
subset,
maintain_order: true,
keep_strategy,
};
let lp = self.get_plan_builder().distinct(options).build();
Self::from_logical_plan(lp, opt_state)
}
/// Drop non-unique rows without maintaining the order of kept rows.
///
/// The order of the kept rows may change; to maintain the original row order, use
/// [`unique_stable`](LazyFrame::unique_stable).
///
/// `subset` is an optional `Vec` of column names to consider for uniqueness; if None,
/// all columns are considered.
pub fn unique(
self,
subset: Option<Vec<String>>,
keep_strategy: UniqueKeepStrategy,
) -> LazyFrame {
self.unique_generic(subset, keep_strategy)
}
pub fn unique_generic<E: AsRef<[IE]>, IE: Into<Selector> + Clone>(
self,
subset: Option<E>,
keep_strategy: UniqueKeepStrategy,
) -> LazyFrame {
let subset = subset.map(|s| {
s.as_ref()
.iter()
.map(|e| e.clone().into())
.collect::<Vec<_>>()
});
let opt_state = self.get_opt_state();
let options = DistinctOptionsDSL {
subset,
maintain_order: false,
keep_strategy,
};
let lp = self.get_plan_builder().distinct(options).build();
Self::from_logical_plan(lp, opt_state)
}
/// Drop rows containing None.
///
/// `subset` is an optional `Vec` of column names to consider for nulls; if None, all
/// columns are considered.
pub fn drop_nulls(self, subset: Option<Vec<Expr>>) -> LazyFrame {
let opt_state = self.get_opt_state();
let lp = self.get_plan_builder().drop_nulls(subset).build();
Self::from_logical_plan(lp, opt_state)
}
/// Slice the DataFrame using an offset (starting row) and a length.
///
/// If `offset` is negative, it is counted from the end of the DataFrame. For
/// instance, `lf.slice(-5, 3)` gets three rows, starting at the row fifth from the
/// end.
///
/// If `offset` and `len` are such that the slice extends beyond the end of the
/// DataFrame, the portion between `offset` and the end will be returned. In this
/// case, the number of rows in the returned DataFrame will be less than `len`.
pub fn slice(self, offset: i64, len: IdxSize) -> LazyFrame {
let opt_state = self.get_opt_state();
let lp = self.get_plan_builder().slice(offset, len).build();
Self::from_logical_plan(lp, opt_state)
}
/// Get the first row.
///
/// Equivalent to `self.slice(0, 1)`.
pub fn first(self) -> LazyFrame {
self.slice(0, 1)
}
/// Get the last row.
///
/// Equivalent to `self.slice(-1, 1)`.
pub fn last(self) -> LazyFrame {
self.slice(-1, 1)
}
/// Get the last `n` rows.
///
/// Equivalent to `self.slice(-(n as i64), n)`.
pub fn tail(self, n: IdxSize) -> LazyFrame {
let neg_tail = -(n as i64);
self.slice(neg_tail, n)
}
/// Unpivot the DataFrame from wide to long format.
///
/// See [`UnpivotArgsIR`] for information on how to unpivot a DataFrame.
#[cfg(feature = "pivot")]
pub fn unpivot(self, args: UnpivotArgsDSL) -> LazyFrame {
let opt_state = self.get_opt_state();
let lp = self.get_plan_builder().unpivot(args).build();
Self::from_logical_plan(lp, opt_state)
}
/// Limit the DataFrame to the first `n` rows.
///
/// Note if you don't want the rows to be scanned, use [`fetch`](LazyFrame::fetch).
pub fn limit(self, n: IdxSize) -> LazyFrame {
self.slice(0, n)
}
/// Apply a function/closure once the logical plan get executed.
///
/// The function has access to the whole materialized DataFrame at the time it is
/// called.
///
/// To apply specific functions to specific columns, use [`Expr::map`] in conjunction
/// with `LazyFrame::with_column` or `with_columns`.
///
/// ## Warning
/// This can blow up in your face if the schema is changed due to the operation. The
/// optimizer relies on a correct schema.
///
/// You can toggle certain optimizations off.
pub fn map<F>(
self,
function: F,
optimizations: AllowedOptimizations,
schema: Option<Arc<dyn UdfSchema>>,
name: Option<&'static str>,
) -> LazyFrame
where
F: 'static + Fn(DataFrame) -> PolarsResult<DataFrame> + Send + Sync,
{
let opt_state = self.get_opt_state();
let lp = self
.get_plan_builder()
.map(
function,
optimizations,
schema,
PlSmallStr::from_static(name.unwrap_or("ANONYMOUS UDF")),
)
.build();
Self::from_logical_plan(lp, opt_state)
}
#[cfg(feature = "python")]
pub fn map_python(
self,
function: polars_plan::prelude::python_udf::PythonFunction,
optimizations: AllowedOptimizations,
schema: Option<SchemaRef>,
validate_output: bool,
) -> LazyFrame {
let opt_state = self.get_opt_state();
let lp = self
.get_plan_builder()
.map_python(function, optimizations, schema, validate_output)
.build();
Self::from_logical_plan(lp, opt_state)
}
pub(crate) fn map_private(self, function: DslFunction) -> LazyFrame {
let opt_state = self.get_opt_state();
let lp = self.get_plan_builder().map_private(function).build();
Self::from_logical_plan(lp, opt_state)
}
/// Add a new column at index 0 that counts the rows.
///
/// `name` is the name of the new column. `offset` is where to start counting from; if
/// `None`, it is set to `0`.
///
/// # Warning
/// This can have a negative effect on query performance. This may for instance block
/// predicate pushdown optimization.
pub fn with_row_index<S>(self, name: S, offset: Option<IdxSize>) -> LazyFrame
where
S: Into<PlSmallStr>,
{
let name = name.into();
match &self.logical_plan {
v @ DslPlan::Scan { scan_type, .. }
if !matches!(scan_type, FileScan::Anonymous { .. }) =>
{
let DslPlan::Scan {
sources,
mut file_options,
scan_type,
file_info,
cached_ir: _,
} = v.clone()
else {
unreachable!()
};
file_options.row_index = Some(RowIndex {
name,
offset: offset.unwrap_or(0),
});
DslPlan::Scan {
sources,
file_options,
scan_type,
file_info,
cached_ir: Default::default(),
}
.into()
},
_ => self.map_private(DslFunction::RowIndex { name, offset }),
}
}
/// Return the number of non-null elements for each column.
pub fn count(self) -> LazyFrame {
self.select(vec![col(PlSmallStr::from_static("*")).count()])
}
/// Unnest the given `Struct` columns: the fields of the `Struct` type will be
/// inserted as columns.
#[cfg(feature = "dtype-struct")]
pub fn unnest<E, IE>(self, cols: E) -> Self
where
E: AsRef<[IE]>,
IE: Into<Selector> + Clone,
{
let cols = cols
.as_ref()
.iter()
.map(|ie| ie.clone().into())
.collect::<Vec<_>>();
self.map_private(DslFunction::Unnest(cols))
}
#[cfg(feature = "merge_sorted")]
pub fn merge_sorted<S>(self, other: LazyFrame, key: S) -> PolarsResult<LazyFrame>
where
S: Into<PlSmallStr>,
{
// The two DataFrames are temporary concatenated
// this indicates until which chunk the data is from the left df
// this trick allows us to reuse the `Union` architecture to get map over
// two DataFrames
let key = key.into();
let left = self.map_private(DslFunction::FunctionIR(FunctionIR::Rechunk));
let q = concat(
&[left, other],
UnionArgs {
rechunk: false,
parallel: true,
..Default::default()
},
)?;
Ok(
q.map_private(DslFunction::FunctionIR(FunctionIR::MergeSorted {
column: key,
})),
)
}
}
/// Utility struct for lazy group_by operation.
#[derive(Clone)]
pub struct LazyGroupBy {
pub logical_plan: DslPlan,
opt_state: OptFlags,
keys: Vec<Expr>,
maintain_order: bool,
#[cfg(feature = "dynamic_group_by")]
dynamic_options: Option<DynamicGroupOptions>,
#[cfg(feature = "dynamic_group_by")]
rolling_options: Option<RollingGroupOptions>,
}
impl From<LazyGroupBy> for LazyFrame {
fn from(lgb: LazyGroupBy) -> Self {
Self {
logical_plan: lgb.logical_plan,
opt_state: lgb.opt_state,
cached_arena: Default::default(),
}
}
}
impl LazyGroupBy {
/// Group by and aggregate.
///
/// Select a column with [col] and choose an aggregation.
/// If you want to aggregate all columns use `col(PlSmallStr::from_static("*"))`.
///
/// # Example
///
/// ```rust
/// use polars_core::prelude::*;
/// use polars_lazy::prelude::*;
/// use arrow::legacy::prelude::QuantileMethod;
///
/// fn example(df: DataFrame) -> LazyFrame {
/// df.lazy()
/// .group_by_stable([col("date")])
/// .agg([
/// col("rain").min().alias("min_rain"),
/// col("rain").sum().alias("sum_rain"),
/// col("rain").quantile(lit(0.5), QuantileMethod::Nearest).alias("median_rain"),
/// ])
/// }
/// ```
pub fn agg<E: AsRef<[Expr]>>(self, aggs: E) -> LazyFrame {
#[cfg(feature = "dynamic_group_by")]
let lp = DslBuilder::from(self.logical_plan)
.group_by(
self.keys,
aggs,
None,
self.maintain_order,
self.dynamic_options,
self.rolling_options,
)
.build();
#[cfg(not(feature = "dynamic_group_by"))]
let lp = DslBuilder::from(self.logical_plan)
.group_by(self.keys, aggs, None, self.maintain_order)
.build();
LazyFrame::from_logical_plan(lp, self.opt_state)
}
/// Return first n rows of each group
pub fn head(self, n: Option<usize>) -> LazyFrame {
let keys = self
.keys
.iter()
.filter_map(|expr| expr_output_name(expr).ok())
.collect::<Vec<_>>();
self.agg([col(PlSmallStr::from_static("*"))
.exclude(keys.iter().cloned())
.head(n)])
.explode_impl(
[col(PlSmallStr::from_static("*")).exclude(keys.iter().cloned())],
true,
)
}
/// Return last n rows of each group
pub fn tail(self, n: Option<usize>) -> LazyFrame {
let keys = self
.keys
.iter()
.filter_map(|expr| expr_output_name(expr).ok())
.collect::<Vec<_>>();
self.agg([col(PlSmallStr::from_static("*"))
.exclude(keys.iter().cloned())
.tail(n)])
.explode_impl(
[col(PlSmallStr::from_static("*")).exclude(keys.iter().cloned())],
true,
)
}
/// Apply a function over the groups as a new DataFrame.
///
/// **It is not recommended that you use this as materializing the DataFrame is very
/// expensive.**
pub fn apply<F>(self, f: F, schema: SchemaRef) -> LazyFrame
where
F: 'static + Fn(DataFrame) -> PolarsResult<DataFrame> + Send + Sync,
{
#[cfg(feature = "dynamic_group_by")]
let options = GroupbyOptions {
dynamic: self.dynamic_options,
rolling: self.rolling_options,
slice: None,
};
#[cfg(not(feature = "dynamic_group_by"))]
let options = GroupbyOptions { slice: None };
let lp = DslPlan::GroupBy {
input: Arc::new(self.logical_plan),
keys: self.keys,
aggs: vec![],
apply: Some((Arc::new(f), schema)),
maintain_order: self.maintain_order,
options: Arc::new(options),
};
LazyFrame::from_logical_plan(lp, self.opt_state)
}
}
#[must_use]
pub struct JoinBuilder {
lf: LazyFrame,
how: JoinType,
other: Option<LazyFrame>,
left_on: Vec<Expr>,
right_on: Vec<Expr>,
allow_parallel: bool,
force_parallel: bool,
suffix: Option<PlSmallStr>,
validation: JoinValidation,
coalesce: JoinCoalesce,
join_nulls: bool,
}
impl JoinBuilder {
/// Create the `JoinBuilder` with the provided `LazyFrame` as the left table.
pub fn new(lf: LazyFrame) -> Self {
Self {
lf,
other: None,
how: JoinType::Inner,
left_on: vec![],
right_on: vec![],
allow_parallel: true,
force_parallel: false,
join_nulls: false,
suffix: None,
validation: Default::default(),
coalesce: Default::default(),
}
}
/// The right table in the join.
pub fn with(mut self, other: LazyFrame) -> Self {
self.other = Some(other);
self
}
/// Select the join type.
pub fn how(mut self, how: JoinType) -> Self {
self.how = how;
self
}
pub fn validate(mut self, validation: JoinValidation) -> Self {
self.validation = validation;
self
}
/// The expressions you want to join both tables on.
///
/// The passed expressions must be valid in both `LazyFrame`s in the join.
pub fn on<E: AsRef<[Expr]>>(mut self, on: E) -> Self {
let on = on.as_ref().to_vec();
self.left_on.clone_from(&on);
self.right_on = on;
self
}
/// The expressions you want to join the left table on.
///
/// The passed expressions must be valid in the left table.
pub fn left_on<E: AsRef<[Expr]>>(mut self, on: E) -> Self {
self.left_on = on.as_ref().to_vec();
self
}
/// The expressions you want to join the right table on.
///
/// The passed expressions must be valid in the right table.
pub fn right_on<E: AsRef<[Expr]>>(mut self, on: E) -> Self {
self.right_on = on.as_ref().to_vec();
self
}
/// Allow parallel table evaluation.
pub fn allow_parallel(mut self, allow: bool) -> Self {
self.allow_parallel = allow;
self
}
/// Force parallel table evaluation.
pub fn force_parallel(mut self, force: bool) -> Self {
self.force_parallel = force;
self
}
/// Join on null values. By default null values will never produce matches.
pub fn join_nulls(mut self, join_nulls: bool) -> Self {
self.join_nulls = join_nulls;
self
}
/// Suffix to add duplicate column names in join.
/// Defaults to `"_right"` if this method is never called.
pub fn suffix<S>(mut self, suffix: S) -> Self
where
S: Into<PlSmallStr>,
{
self.suffix = Some(suffix.into());
self
}
/// Whether to coalesce join columns.
pub fn coalesce(mut self, coalesce: JoinCoalesce) -> Self {
self.coalesce = coalesce;
self
}
/// Finish builder
pub fn finish(self) -> LazyFrame {
let mut opt_state = self.lf.opt_state;
let other = self.other.expect("'with' not set in join builder");
// If any of the nodes reads from files we must activate this plan as well.
if other.opt_state.contains(OptFlags::FILE_CACHING) {
opt_state |= OptFlags::FILE_CACHING;
}
let args = JoinArgs {
how: self.how,
validation: self.validation,
suffix: self.suffix,
slice: None,
join_nulls: self.join_nulls,
coalesce: self.coalesce,
};
let lp = self
.lf
.get_plan_builder()
.join(
other.logical_plan,
self.left_on,
self.right_on,
JoinOptions {
allow_parallel: self.allow_parallel,
force_parallel: self.force_parallel,
args,
..Default::default()
}
.into(),
)
.build();
LazyFrame::from_logical_plan(lp, opt_state)
}
// Finish with join predicates
pub fn join_where(self, predicates: Vec<Expr>) -> LazyFrame {
let mut opt_state = self.lf.opt_state;
let other = self.other.expect("with not set");
// If any of the nodes reads from files we must activate this plan as well.
if other.opt_state.contains(OptFlags::FILE_CACHING) {
opt_state |= OptFlags::FILE_CACHING;
}
// Decompose `And` conjunctions into their component expressions
fn decompose_and(predicate: Expr, expanded_predicates: &mut Vec<Expr>) {
if let Expr::BinaryExpr {
op: Operator::And,
left,
right,
} = predicate
{
decompose_and((*left).clone(), expanded_predicates);
decompose_and((*right).clone(), expanded_predicates);
} else {
expanded_predicates.push(predicate);
}
}
let mut expanded_predicates = Vec::with_capacity(predicates.len() * 2);
for predicate in predicates {
decompose_and(predicate, &mut expanded_predicates);
}
let predicates: Vec<Expr> = expanded_predicates;
// Decompose `is_between` predicates to allow for cleaner expression of range joins
#[cfg(feature = "is_between")]
let predicates: Vec<Expr> = {
let mut expanded_predicates = Vec::with_capacity(predicates.len() * 2);
for predicate in predicates {
if let Expr::Function {
function: FunctionExpr::Boolean(BooleanFunction::IsBetween { closed }),
input,
..
} = &predicate
{
if let [expr, lower, upper] = input.as_slice() {
match closed {
ClosedInterval::Both => {
expanded_predicates.push(expr.clone().gt_eq(lower.clone()));
expanded_predicates.push(expr.clone().lt_eq(upper.clone()));
},
ClosedInterval::Right => {
expanded_predicates.push(expr.clone().gt(lower.clone()));
expanded_predicates.push(expr.clone().lt_eq(upper.clone()));
},
ClosedInterval::Left => {
expanded_predicates.push(expr.clone().gt_eq(lower.clone()));
expanded_predicates.push(expr.clone().lt(upper.clone()));
},
ClosedInterval::None => {
expanded_predicates.push(expr.clone().gt(lower.clone()));
expanded_predicates.push(expr.clone().lt(upper.clone()));
},
}
continue;
}
}
expanded_predicates.push(predicate);
}
expanded_predicates
};
let args = JoinArgs {
how: self.how,
validation: self.validation,
suffix: self.suffix,
slice: None,
join_nulls: self.join_nulls,
coalesce: self.coalesce,
};
let options = JoinOptions {
allow_parallel: self.allow_parallel,
force_parallel: self.force_parallel,
args,
..Default::default()
};
let lp = DslPlan::Join {
input_left: Arc::new(self.lf.logical_plan),
input_right: Arc::new(other.logical_plan),
left_on: Default::default(),
right_on: Default::default(),
predicates,
options: Arc::from(options),
};
LazyFrame::from_logical_plan(lp, opt_state)
}
}