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
//! Free functions that create iterator adaptors or call iterator methods.
//!
//! The benefit of free functions is that they accept any [`IntoIterator`] as
//! argument, so the resulting code may be easier to read.
#[cfg(feature = "use_alloc")]
use std::fmt::Display;
use std::iter::{self, Zip};
#[cfg(feature = "use_alloc")]
type VecIntoIter<T> = alloc::vec::IntoIter<T>;
#[cfg(feature = "use_alloc")]
use alloc::{
string::String,
};
use crate::Itertools;
use crate::intersperse::{Intersperse, IntersperseWith};
pub use crate::adaptors::{
interleave,
merge,
put_back,
};
#[cfg(feature = "use_alloc")]
pub use crate::put_back_n_impl::put_back_n;
#[cfg(feature = "use_alloc")]
pub use crate::multipeek_impl::multipeek;
#[cfg(feature = "use_alloc")]
pub use crate::peek_nth::peek_nth;
#[cfg(feature = "use_alloc")]
pub use crate::kmerge_impl::kmerge;
pub use crate::zip_eq_impl::zip_eq;
pub use crate::merge_join::merge_join_by;
#[cfg(feature = "use_alloc")]
pub use crate::rciter_impl::rciter;
/// Iterate `iterable` with a particular value inserted between each element.
///
/// [`IntoIterator`] enabled version of [`Iterator::intersperse`].
///
/// ```
/// use itertools::intersperse;
///
/// itertools::assert_equal(intersperse((0..3), 8), vec![0, 8, 1, 8, 2]);
/// ```
pub fn intersperse<I>(iterable: I, element: I::Item) -> Intersperse<I::IntoIter>
where I: IntoIterator,
<I as IntoIterator>::Item: Clone
{
Itertools::intersperse(iterable.into_iter(), element)
}
/// Iterate `iterable` with a particular value created by a function inserted
/// between each element.
///
/// [`IntoIterator`] enabled version of [`Iterator::intersperse_with`].
///
/// ```
/// use itertools::intersperse_with;
///
/// let mut i = 10;
/// itertools::assert_equal(intersperse_with((0..3), || { i -= 1; i }), vec![0, 9, 1, 8, 2]);
/// assert_eq!(i, 8);
/// ```
pub fn intersperse_with<I, F>(iterable: I, element: F) -> IntersperseWith<I::IntoIter, F>
where I: IntoIterator,
F: FnMut() -> I::Item
{
Itertools::intersperse_with(iterable.into_iter(), element)
}
/// Iterate `iterable` with a running index.
///
/// [`IntoIterator`] enabled version of [`Iterator::enumerate`].
///
/// ```
/// use itertools::enumerate;
///
/// for (i, elt) in enumerate(&[1, 2, 3]) {
/// /* loop body */
/// }
/// ```
pub fn enumerate<I>(iterable: I) -> iter::Enumerate<I::IntoIter>
where I: IntoIterator
{
iterable.into_iter().enumerate()
}
/// Iterate `iterable` in reverse.
///
/// [`IntoIterator`] enabled version of [`Iterator::rev`].
///
/// ```
/// use itertools::rev;
///
/// for elt in rev(&[1, 2, 3]) {
/// /* loop body */
/// }
/// ```
pub fn rev<I>(iterable: I) -> iter::Rev<I::IntoIter>
where I: IntoIterator,
I::IntoIter: DoubleEndedIterator
{
iterable.into_iter().rev()
}
/// Converts the arguments to iterators and zips them.
///
/// [`IntoIterator`] enabled version of [`Iterator::zip`].
///
/// ## Example
///
/// ```
/// use itertools::zip;
///
/// let mut result: Vec<(i32, char)> = Vec::new();
///
/// for (a, b) in zip(&[1, 2, 3, 4, 5], &['a', 'b', 'c']) {
/// result.push((*a, *b));
/// }
/// assert_eq!(result, vec![(1, 'a'),(2, 'b'),(3, 'c')]);
/// ```
#[deprecated(note="Use [std::iter::zip](https://doc.rust-lang.org/std/iter/fn.zip.html) instead", since="0.10.4")]
pub fn zip<I, J>(i: I, j: J) -> Zip<I::IntoIter, J::IntoIter>
where I: IntoIterator,
J: IntoIterator
{
i.into_iter().zip(j)
}
/// Takes two iterables and creates a new iterator over both in sequence.
///
/// [`IntoIterator`] enabled version of [`Iterator::chain`].
///
/// ## Example
/// ```
/// use itertools::chain;
///
/// let mut result:Vec<i32> = Vec::new();
///
/// for element in chain(&[1, 2, 3], &[4]) {
/// result.push(*element);
/// }
/// assert_eq!(result, vec![1, 2, 3, 4]);
/// ```
pub fn chain<I, J>(i: I, j: J) -> iter::Chain<<I as IntoIterator>::IntoIter, <J as IntoIterator>::IntoIter>
where I: IntoIterator,
J: IntoIterator<Item = I::Item>
{
i.into_iter().chain(j)
}
/// Create an iterator that clones each element from &T to T
///
/// [`IntoIterator`] enabled version of [`Iterator::cloned`].
///
/// ```
/// use itertools::cloned;
///
/// assert_eq!(cloned(b"abc").next(), Some(b'a'));
/// ```
pub fn cloned<'a, I, T: 'a>(iterable: I) -> iter::Cloned<I::IntoIter>
where I: IntoIterator<Item=&'a T>,
T: Clone,
{
iterable.into_iter().cloned()
}
/// Perform a fold operation over the iterable.
///
/// [`IntoIterator`] enabled version of [`Iterator::fold`].
///
/// ```
/// use itertools::fold;
///
/// assert_eq!(fold(&[1., 2., 3.], 0., |a, &b| f32::max(a, b)), 3.);
/// ```
pub fn fold<I, B, F>(iterable: I, init: B, f: F) -> B
where I: IntoIterator,
F: FnMut(B, I::Item) -> B
{
iterable.into_iter().fold(init, f)
}
/// Test whether the predicate holds for all elements in the iterable.
///
/// [`IntoIterator`] enabled version of [`Iterator::all`].
///
/// ```
/// use itertools::all;
///
/// assert!(all(&[1, 2, 3], |elt| *elt > 0));
/// ```
pub fn all<I, F>(iterable: I, f: F) -> bool
where I: IntoIterator,
F: FnMut(I::Item) -> bool
{
iterable.into_iter().all(f)
}
/// Test whether the predicate holds for any elements in the iterable.
///
/// [`IntoIterator`] enabled version of [`Iterator::any`].
///
/// ```
/// use itertools::any;
///
/// assert!(any(&[0, -1, 2], |elt| *elt > 0));
/// ```
pub fn any<I, F>(iterable: I, f: F) -> bool
where I: IntoIterator,
F: FnMut(I::Item) -> bool
{
iterable.into_iter().any(f)
}
/// Return the maximum value of the iterable.
///
/// [`IntoIterator`] enabled version of [`Iterator::max`].
///
/// ```
/// use itertools::max;
///
/// assert_eq!(max(0..10), Some(9));
/// ```
pub fn max<I>(iterable: I) -> Option<I::Item>
where I: IntoIterator,
I::Item: Ord
{
iterable.into_iter().max()
}
/// Return the minimum value of the iterable.
///
/// [`IntoIterator`] enabled version of [`Iterator::min`].
///
/// ```
/// use itertools::min;
///
/// assert_eq!(min(0..10), Some(0));
/// ```
pub fn min<I>(iterable: I) -> Option<I::Item>
where I: IntoIterator,
I::Item: Ord
{
iterable.into_iter().min()
}
/// Combine all iterator elements into one String, separated by `sep`.
///
/// [`IntoIterator`] enabled version of [`Itertools::join`].
///
/// ```
/// use itertools::join;
///
/// assert_eq!(join(&[1, 2, 3], ", "), "1, 2, 3");
/// ```
#[cfg(feature = "use_alloc")]
pub fn join<I>(iterable: I, sep: &str) -> String
where I: IntoIterator,
I::Item: Display
{
iterable.into_iter().join(sep)
}
/// Sort all iterator elements into a new iterator in ascending order.
///
/// [`IntoIterator`] enabled version of [`Itertools::sorted`].
///
/// ```
/// use itertools::sorted;
/// use itertools::assert_equal;
///
/// assert_equal(sorted("rust".chars()), "rstu".chars());
/// ```
#[cfg(feature = "use_alloc")]
pub fn sorted<I>(iterable: I) -> VecIntoIter<I::Item>
where I: IntoIterator,
I::Item: Ord
{
iterable.into_iter().sorted()
}