polars_utils/itertools/
mod.rs

1use std::cmp::Ordering;
2
3use crate::IdxSize;
4
5pub mod enumerate_idx;
6
7/// Utility extension trait of iterator methods.
8pub trait Itertools: Iterator {
9    /// Equivalent to `.collect::<Vec<_>>()`.
10    fn collect_vec(self) -> Vec<Self::Item>
11    where
12        Self: Sized,
13    {
14        self.collect()
15    }
16
17    /// Equivalent to `.collect::<Result<_, _>>()`.
18    fn try_collect<T, U, E>(self) -> Result<U, E>
19    where
20        Self: Sized + Iterator<Item = Result<T, E>>,
21        Result<U, E>: FromIterator<Result<T, E>>,
22    {
23        self.collect()
24    }
25
26    /// Equivalent to `.collect::<Result<Vec<_>, _>>()`.
27    fn try_collect_vec<T, U, E>(self) -> Result<Vec<U>, E>
28    where
29        Self: Sized + Iterator<Item = Result<T, E>>,
30        Result<Vec<U>, E>: FromIterator<Result<T, E>>,
31    {
32        self.collect()
33    }
34
35    fn enumerate_idx(self) -> enumerate_idx::EnumerateIdx<Self, IdxSize>
36    where
37        Self: Sized,
38    {
39        enumerate_idx::EnumerateIdx::new(self)
40    }
41
42    fn enumerate_u32(self) -> enumerate_idx::EnumerateIdx<Self, u32>
43    where
44        Self: Sized,
45    {
46        enumerate_idx::EnumerateIdx::new(self)
47    }
48
49    fn all_equal(mut self) -> bool
50    where
51        Self: Sized,
52        Self::Item: PartialEq,
53    {
54        match self.next() {
55            None => true,
56            Some(a) => self.all(|x| a == x),
57        }
58    }
59
60    // Stable copy of the unstable eq_by from the stdlib.
61    fn eq_by_<I, F>(mut self, other: I, mut eq: F) -> bool
62    where
63        Self: Sized,
64        I: IntoIterator,
65        F: FnMut(Self::Item, I::Item) -> bool,
66    {
67        let mut other = other.into_iter();
68        loop {
69            match (self.next(), other.next()) {
70                (None, None) => return true,
71                (None, Some(_)) => return false,
72                (Some(_), None) => return false,
73                (Some(l), Some(r)) => {
74                    if eq(l, r) {
75                        continue;
76                    } else {
77                        return false;
78                    }
79                },
80            }
81        }
82    }
83
84    // Stable copy of the unstable partial_cmp_by from the stdlib.
85    fn partial_cmp_by_<I, F>(mut self, other: I, mut partial_cmp: F) -> Option<Ordering>
86    where
87        Self: Sized,
88        I: IntoIterator,
89        F: FnMut(Self::Item, I::Item) -> Option<Ordering>,
90    {
91        let mut other = other.into_iter();
92        loop {
93            match (self.next(), other.next()) {
94                (None, None) => return Some(Ordering::Equal),
95                (None, Some(_)) => return Some(Ordering::Less),
96                (Some(_), None) => return Some(Ordering::Greater),
97                (Some(l), Some(r)) => match partial_cmp(l, r) {
98                    Some(Ordering::Equal) => continue,
99                    ord => return ord,
100                },
101            }
102        }
103    }
104}
105
106impl<T: Iterator + ?Sized> Itertools for T {}
polars_utils/itertools/mod.rs

polars_utils/itertools/
mod.rs
