String#
Function |
Description |
|---|---|
Returns the length of the input string in bits. |
|
Returns all input expressions concatenated together as a string. |
|
Returns all input expressions concatenated together (and interleaved with a separator) as a string. |
|
Converts a formatted date string to an actual Date value. |
|
Returns True if the value ends with the second argument. |
|
Returns the value with the first letter capitalized. |
|
Returns the first (leftmost) |
|
Returns the character length of the string. |
|
Returns a lowercased column. |
|
Strips whitespaces from the left. |
|
Returns the length of a given string in bytes. |
|
Returns True if |
|
Replaces a given substring with another string. |
|
Returns the reversed string. |
|
Returns the last (rightmost) |
|
Strips whitespaces from the right. |
|
Returns True if the value starts with the second argument. |
|
Returns the index of the given substring in the target string. |
|
Converts a string to a Datetime using a strftime-compatible formatting string. |
|
Returns a portion of the data (first character = 1) in the range [start, start + length]. |
|
Converts a formatted timestamp/datetime string to an actual Datetime value. |
|
Returns an uppercased column. |
BIT_LENGTH#
Returns the length of the input string in bits.
Example:
df = pl.DataFrame({"foo": ["a", "bb", "ccc", "dddd"]})
df.sql("""
SELECT foo, BIT_LENGTH(foo) AS n_bits FROM self
""")
# shape: (4, 2)
# ┌──────┬────────┐
# │ foo ┆ n_bits │
# │ --- ┆ --- │
# │ str ┆ u32 │
# ╞══════╪════════╡
# │ a ┆ 8 │
# │ bb ┆ 16 │
# │ ccc ┆ 24 │
# │ dddd ┆ 32 │
# └──────┴────────┘
CONCAT#
Returns all input expressions concatenated together as a string.
Example:
df = pl.DataFrame(
{
"foo": ["aa", "b", "c", "dd"],
"bar": ["zz", "yy", "xx", "ww"],
}
)
df.sql("""
SELECT CONCAT(foo, bar) AS foobar FROM self
""")
# shape: (4, 1)
# ┌────────┐
# │ foobar │
# │ --- │
# │ str │
# ╞════════╡
# │ aazz │
# │ byy │
# │ cxx │
# │ ddww │
# └────────┘
CONCAT_WS#
Returns all input expressions concatenated together (and interleaved with a separator) as a string.
Example:
df = pl.DataFrame(
{
"foo": ["aa", "b", "c", "dd"],
"bar": ["zz", "yy", "xx", "ww"],
}
)
df.sql("""
SELECT CONCAT_WS(':', foo, bar) AS foobar FROM self
""")
# shape: (4, 1)
# ┌────────┐
# │ foobar │
# │ --- │
# │ str │
# ╞════════╡
# │ aa:zz │
# │ b:yy │
# │ c:xx │
# │ dd:ww │
# └────────┘
DATE#
Converts a formatted string date to an actual Date type; ISO-8601 format is assumed unless a strftime-compatible formatting string is provided as the second parameter.
Tip
DATE is also supported as a typed literal (this form does not allow a format string).
SELECT DATE '2021-01-01' AS dt
Example:
df = pl.DataFrame(
{
"s_dt1": ["1969-10-30", "2024-07-05", "2077-02-28"],
"s_dt2": ["10 February 1920", "5 July 2077", "28 April 2000"],
}
)
df.sql("""
SELECT
DATE(s_dt1) AS dt1,
DATE(s_dt2, '%d %B %Y') AS dt2
FROM self
""")
# shape: (3, 2)
# ┌────────────┬────────────┐
# │ dt1 ┆ dt2 │
# │ --- ┆ --- │
# │ date ┆ date │
# ╞════════════╪════════════╡
# │ 1969-10-30 ┆ 1920-02-10 │
# │ 2024-07-05 ┆ 2077-07-05 │
# │ 2077-02-28 ┆ 2000-04-28 │
# └────────────┴────────────┘
ENDS_WITH#
Returns True if the value ends with the second argument.
Example:
df = pl.DataFrame(
{
"foo": ["aa", "bb", "cc", "dd"],
"bar": ["zz", "yy", "xx", "ww"],
}
)
df.sql("""
SELECT foo, ENDS_WITH(foo, 'a') AS ends_a FROM self
""")
# shape: (4, 2)
# ┌─────┬────────┐
# │ foo ┆ ends_a │
# │ --- ┆ --- │
# │ str ┆ bool │
# ╞═════╪════════╡
# │ aa ┆ true │
# │ bb ┆ false │
# │ cc ┆ false │
# │ dd ┆ false │
# └─────┴────────┘
INITCAP#
Returns the value with the first letter capitalized.
Example:
df = pl.DataFrame({"bar": ["zz", "yy", "xx", "ww"]})
df.sql("""
SELECT bar, INITCAP(bar) AS baz FROM self
""")
# shape: (4, 2)
# ┌─────┬─────┐
# │ bar ┆ baz │
# │ --- ┆ --- │
# │ str ┆ str │
# ╞═════╪═════╡
# │ zz ┆ Zz │
# │ yy ┆ Yy │
# │ xx ┆ Xx │
# │ ww ┆ Ww │
# └─────┴─────┘
LEFT#
Returns the first (leftmost) n characters.
Example:
df = pl.DataFrame(
{
"foo": ["abcd", "efgh", "ijkl", "mnop"],
"bar": ["zz", "yy", "xx", "ww"],
}
)
df.sql("""
SELECT
LEFT(foo, 1) AS foo1,
LEFT(bar, 2) AS bar2
FROM self
""")
# shape: (4, 2)
# ┌──────┬──────┐
# │ foo1 ┆ bar2 │
# │ --- ┆ --- │
# │ str ┆ str │
# ╞══════╪══════╡
# │ a ┆ zz │
# │ e ┆ yy │
# │ i ┆ xx │
# │ m ┆ ww │
# └──────┴──────┘
LENGTH#
Returns the character length of the string.
Aliases
CHAR_LENGTH, CHARACTER_LENGTH
Example:
df = pl.DataFrame(
{
"iso_lang":["de", "ru", "es"],
"color": ["weiß", "синий", "amarillo"],
}
)
df.sql("""
SELECT
iso_lang,
color,
LENGTH(color) AS n_chars,
OCTET_LENGTH(color) AS n_bytes
FROM self
""")
# shape: (3, 4)
# ┌──────────┬──────────┬─────────┬─────────┐
# │ iso_lang ┆ color ┆ n_chars ┆ n_bytes │
# │ --- ┆ --- ┆ --- ┆ --- │
# │ str ┆ str ┆ u32 ┆ u32 │
# ╞══════════╪══════════╪═════════╪═════════╡
# │ de ┆ weiß ┆ 4 ┆ 5 │
# │ ru ┆ синий ┆ 5 ┆ 10 │
# │ es ┆ amarillo ┆ 8 ┆ 8 │
# └──────────┴──────────┴─────────┴─────────┘
LOWER#
Returns a lowercased column.
Example:
df = pl.DataFrame({"foo": ["AA", "BB", "CC", "DD"]})
df.sql("""
SELECT foo, LOWER(foo) AS foo_lower FROM self
""")
# shape: (4, 2)
# ┌─────┬───────────┐
# │ foo ┆ foo_lower │
# │ --- ┆ --- │
# │ str ┆ str │
# ╞═════╪═══════════╡
# │ AA ┆ aa │
# │ BB ┆ bb │
# │ CC ┆ cc │
# │ DD ┆ dd │
# └─────┴───────────┘
LTRIM#
Strips whitespaces from the left.
Example:
df = pl.DataFrame({"foo": [" AA", " BB", "CC", " DD"]})
df.sql("""
SELECT foo, LTRIM(foo) AS trimmed FROM self
""")
# shape: (4, 2)
# ┌───────┬─────────┐
# │ foo ┆ trimmed │
# │ --- ┆ --- │
# │ str ┆ str │
# ╞═══════╪═════════╡
# │ AA ┆ AA │
# │ BB ┆ BB │
# │ CC ┆ CC │
# │ DD ┆ DD │
# └───────┴─────────┘
OCTET_LENGTH#
Returns the length of a given string in bytes.
Example:
df = pl.DataFrame(
{
"iso_lang":["de", "ru", "es"],
"color": ["weiß", "синий", "amarillo"],
}
)
df.sql("""
SELECT
iso_lang,
color,
OCTET_LENGTH(color) AS n_bytes,
LENGTH(color) AS n_chars
FROM self
""")
# shape: (3, 4)
# ┌──────────┬──────────┬─────────┬─────────┐
# │ iso_lang ┆ color ┆ n_bytes ┆ n_chars │
# │ --- ┆ --- ┆ --- ┆ --- │
# │ str ┆ str ┆ u32 ┆ u32 │
# ╞══════════╪══════════╪═════════╪═════════╡
# │ de ┆ weiß ┆ 5 ┆ 4 │
# │ ru ┆ синий ┆ 10 ┆ 5 │
# │ es ┆ amarillo ┆ 8 ┆ 8 │
# └──────────┴──────────┴─────────┴─────────┘
REGEXP_LIKE#
Returns True if pattern matches the value (optional: flags).
Example:
df = pl.DataFrame({"foo": ["abc123", "4ab4a", "abc456", "321cba"]})
df.sql(r"""
SELECT foo, REGEXP_LIKE(foo, '\d$') AS ends_in_digit FROM self
""")
# shape: (4, 2)
# ┌────────┬───────────────┐
# │ foo ┆ ends_in_digit │
# │ --- ┆ --- │
# │ str ┆ bool │
# ╞════════╪═══════════════╡
# │ abc123 ┆ true │
# │ 4ab4a ┆ false │
# │ abc456 ┆ true │
# │ 321cba ┆ false │
# └────────┴───────────────┘
REPLACE#
Replaces a given substring with another string.
Example:
df = pl.DataFrame({"foo": ["abc123", "11aabb", "bcbc45"]})
df.sql("""
SELECT foo, REPLACE(foo, 'b', '?') AS bar FROM self
""")
# shape: (3, 2)
# ┌────────┬────────┐
# │ foo ┆ bar │
# │ --- ┆ --- │
# │ str ┆ str │
# ╞════════╪════════╡
# │ abc123 ┆ a?c123 │
# │ 11aabb ┆ 11aa?? │
# │ bcbc45 ┆ ?c?c45 │
# └────────┴────────┘
REVERSE#
Returns the reversed string.
Example:
df = pl.DataFrame({"foo": ["apple", "banana", "orange", "grape"]})
df.sql("""
SELECT foo, REVERSE(foo) AS oof FROM self
""")
# shape: (4, 2)
# ┌────────┬────────┐
# │ foo ┆ oof │
# │ --- ┆ --- │
# │ str ┆ str │
# ╞════════╪════════╡
# │ apple ┆ elppa │
# │ banana ┆ ananab │
# │ orange ┆ egnaro │
# │ grape ┆ eparg │
# └────────┴────────┘
RIGHT#
Returns the last (rightmost) n characters.
Example:
df = pl.DataFrame({"foo": ["ab", "cde", "fghi", "jklmn"]})
df.sql("""
SELECT foo, RIGHT(foo, 2) AS bar FROM self
""")
# shape: (4, 2)
# ┌───────┬─────┐
# │ foo ┆ bar │
# │ --- ┆ --- │
# │ str ┆ str │
# ╞═══════╪═════╡
# │ ab ┆ ab │
# │ cde ┆ de │
# │ fghi ┆ hi │
# │ jklmn ┆ mn │
# └───────┴─────┘
RTRIM#
Strips whitespaces from the right.
Example:
df = pl.DataFrame({"bar": ["zz ", "yy ", "xx ", "ww "]})
df.sql("""
SELECT bar, RTRIM(bar) AS baz FROM self
""")
# shape: (4, 2)
# ┌────────┬─────┐
# │ bar ┆ baz │
# │ --- ┆ --- │
# │ str ┆ str │
# ╞════════╪═════╡
# │ zz ┆ zz │
# │ yy ┆ yy │
# │ xx ┆ xx │
# │ ww ┆ ww │
# └────────┴─────┘
STARTS_WITH#
Returns True if the value starts with the second argument.
Example:
df = pl.DataFrame({"foo": ["apple", "banana", "avocado", "grape"]})
df.sql("""
SELECT foo, STARTS_WITH(foo, 'a') AS starts_a FROM self
""")
# shape: (4, 2)
# ┌─────────┬──────────┐
# │ foo ┆ starts_a │
# │ --- ┆ --- │
# │ str ┆ bool │
# ╞═════════╪══════════╡
# │ apple ┆ true │
# │ banana ┆ false │
# │ avocado ┆ true │
# │ grape ┆ false │
# └─────────┴──────────┘
STRPOS#
Returns the index of the given substring in the target string.
Example:
df = pl.DataFrame({"foo": ["apple", "banana", "orange", "grape"]})
df.sql("""
SELECT foo, STRPOS(foo, 'a') AS pos_a FROM self
""")
# shape: (4, 2)
# ┌────────┬───────┐
# │ foo ┆ pos_a │
# │ --- ┆ --- │
# │ str ┆ u32 │
# ╞════════╪═══════╡
# │ apple ┆ 1 │
# │ banana ┆ 2 │
# │ orange ┆ 3 │
# │ grape ┆ 3 │
# └────────┴───────┘
STRPTIME#
Converts a string to a Datetime using a chrono strftime-compatible formatting string.
Example:
df = pl.DataFrame(
{
"s_dt": ["1969 Oct 30", "2024 Jul 05", "2077 Feb 28"],
"s_tm": ["00.30.55", "12.40.15", "10.45.00"],
}
)
df.sql("""
SELECT
s_dt,
s_tm,
STRPTIME(s_dt || ' ' || s_tm, '%Y %b %d %H.%M.%S') AS dtm
FROM self
""")
# shape: (3, 3)
# ┌─────────────┬──────────┬─────────────────────┐
# │ s_dt ┆ s_tm ┆ dtm │
# │ --- ┆ --- ┆ --- │
# │ str ┆ str ┆ datetime[μs] │
# ╞═════════════╪══════════╪═════════════════════╡
# │ 1969 Oct 30 ┆ 00.30.55 ┆ 1969-10-30 00:30:55 │
# │ 2024 Jul 05 ┆ 12.40.15 ┆ 2024-07-05 12:40:15 │
# │ 2077 Feb 28 ┆ 10.45.00 ┆ 2077-02-28 10:45:00 │
# └─────────────┴──────────┴─────────────────────┘
SUBSTR#
Returns a slice of the string data (1-indexed) in the range [start, start + length].
Example:
df = pl.DataFrame({"foo": ["apple", "banana", "orange", "grape"]})
df.sql("""
SELECT foo, SUBSTR(foo, 3, 4) AS foo_3_4 FROM self
""")
# shape: (4, 2)
# ┌────────┬─────────┐
# │ foo ┆ foo_3_4 │
# │ --- ┆ --- │
# │ str ┆ str │
# ╞════════╪═════════╡
# │ apple ┆ ple │
# │ banana ┆ nana │
# │ orange ┆ ange │
# │ grape ┆ ape │
# └────────┴─────────┘
TIMESTAMP#
Converts a formatted string date to an actual Datetime type; ISO-8601 format is assumed unless a strftime-compatible formatting string is provided as the second parameter.
Aliases
DATETIME
Tip
TIMESTAMP is also supported as a typed literal (this form does not allow a format string).
SELECT TIMESTAMP '2077-12-10 22:30:45' AS ts
Example:
df = pl.DataFrame(
{
"str_timestamp": [
"1969 July 30, 00:30:55",
"2030-October-08, 12:40:15",
"2077 February 28, 10:45:00",
]
}
)
df.sql("""
SELECT str_timestamp, TIMESTAMP(str_date, '%Y.%m.%d') AS date FROM self
""")
# shape: (3, 2)
# ┌────────────┬────────────┐
# │ str_date ┆ date │
# │ --- ┆ --- │
# │ str ┆ date │
# ╞════════════╪════════════╡
# │ 1969.10.30 ┆ 1969-10-30 │
# │ 2024.07.05 ┆ 2024-07-05 │
# │ 2077.02.28 ┆ 2077-02-28 │
# └────────────┴────────────┘
UPPER#
Returns an uppercased column.
Example:
df = pl.DataFrame({"foo": ["apple", "banana", "orange", "grape"]})
df.sql("""
SELECT foo, UPPER(foo) AS foo_upper FROM self
""")
# shape: (4, 2)
# ┌────────┬───────────┐
# │ foo ┆ foo_upper │
# │ --- ┆ --- │
# │ str ┆ str │
# ╞════════╪═══════════╡
# │ apple ┆ APPLE │
# │ banana ┆ BANANA │
# │ orange ┆ ORANGE │
# │ grape ┆ GRAPE │
# └────────┴───────────┘