1 // Copyright 2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
12 use core::{i8, i16, isize};
17 let empty: [isize; 0] = [];
21 assert!(!xs.iter().lt(ys.iter()));
22 assert!(!xs.iter().le(ys.iter()));
23 assert!( xs.iter().gt(ys.iter()));
24 assert!( xs.iter().ge(ys.iter()));
26 assert!( ys.iter().lt(xs.iter()));
27 assert!( ys.iter().le(xs.iter()));
28 assert!(!ys.iter().gt(xs.iter()));
29 assert!(!ys.iter().ge(xs.iter()));
31 assert!( empty.iter().lt(xs.iter()));
32 assert!( empty.iter().le(xs.iter()));
33 assert!(!empty.iter().gt(xs.iter()));
34 assert!(!empty.iter().ge(xs.iter()));
37 let u = [1.0f64, 2.0];
38 let v = [0.0f64/0.0, 3.0];
40 assert!(!u.iter().lt(v.iter()));
41 assert!(!u.iter().le(v.iter()));
42 assert!(!u.iter().gt(v.iter()));
43 assert!(!u.iter().ge(v.iter()));
49 assert!(a.iter().lt(b.iter()) == (a[0] < b[0]));
50 assert!(a.iter().le(b.iter()) == (a[0] <= b[0]));
51 assert!(a.iter().gt(b.iter()) == (a[0] > b[0]));
52 assert!(a.iter().ge(b.iter()) == (a[0] >= b[0]));
54 assert!(c.iter().lt(b.iter()) == (c[0] < b[0]));
55 assert!(c.iter().le(b.iter()) == (c[0] <= b[0]));
56 assert!(c.iter().gt(b.iter()) == (c[0] > b[0]));
57 assert!(c.iter().ge(b.iter()) == (c[0] >= b[0]));
61 fn test_multi_iter() {
64 assert!(xs.iter().eq(ys.iter().rev()));
65 assert!(xs.iter().lt(xs.iter().skip(2)));
69 fn test_counter_from_iter() {
70 let it = (0..).step_by(5).take(10);
71 let xs: Vec<isize> = FromIterator::from_iter(it);
72 assert_eq!(xs, [0, 5, 10, 15, 20, 25, 30, 35, 40, 45]);
76 fn test_iterator_chain() {
77 let xs = [0, 1, 2, 3, 4, 5];
78 let ys = [30, 40, 50, 60];
79 let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
80 let it = xs.iter().chain(&ys);
83 assert_eq!(x, expected[i]);
86 assert_eq!(i, expected.len());
88 let ys = (30..).step_by(10).take(4);
89 let it = xs.iter().cloned().chain(ys);
92 assert_eq!(x, expected[i]);
95 assert_eq!(i, expected.len());
99 fn test_iterator_chain_nth() {
100 let xs = [0, 1, 2, 3, 4, 5];
101 let ys = [30, 40, 50, 60];
103 let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
104 for (i, x) in expected.iter().enumerate() {
105 assert_eq!(Some(x), xs.iter().chain(&ys).nth(i));
107 assert_eq!(zs.iter().chain(&xs).nth(0), Some(&0));
109 let mut it = xs.iter().chain(&zs);
110 assert_eq!(it.nth(5), Some(&5));
111 assert_eq!(it.next(), None);
115 fn test_iterator_chain_last() {
116 let xs = [0, 1, 2, 3, 4, 5];
117 let ys = [30, 40, 50, 60];
119 assert_eq!(xs.iter().chain(&ys).last(), Some(&60));
120 assert_eq!(zs.iter().chain(&ys).last(), Some(&60));
121 assert_eq!(ys.iter().chain(&zs).last(), Some(&60));
122 assert_eq!(zs.iter().chain(&zs).last(), None);
126 fn test_iterator_chain_count() {
127 let xs = [0, 1, 2, 3, 4, 5];
128 let ys = [30, 40, 50, 60];
130 assert_eq!(xs.iter().chain(&ys).count(), 10);
131 assert_eq!(zs.iter().chain(&ys).count(), 4);
135 fn test_iterator_chain_find() {
136 let xs = [0, 1, 2, 3, 4, 5];
137 let ys = [30, 40, 50, 60];
138 let mut iter = xs.iter().chain(&ys);
139 assert_eq!(iter.find(|&&i| i == 4), Some(&4));
140 assert_eq!(iter.next(), Some(&5));
141 assert_eq!(iter.find(|&&i| i == 40), Some(&40));
142 assert_eq!(iter.next(), Some(&50));
143 assert_eq!(iter.find(|&&i| i == 100), None);
144 assert_eq!(iter.next(), None);
148 fn test_filter_map() {
149 let it = (0..).step_by(1).take(10)
150 .filter_map(|x| if x % 2 == 0 { Some(x*x) } else { None });
151 assert_eq!(it.collect::<Vec<usize>>(), [0*0, 2*2, 4*4, 6*6, 8*8]);
155 fn test_iterator_enumerate() {
156 let xs = [0, 1, 2, 3, 4, 5];
157 let it = xs.iter().enumerate();
164 fn test_iterator_enumerate_nth() {
165 let xs = [0, 1, 2, 3, 4, 5];
166 for (i, &x) in xs.iter().enumerate() {
170 let mut it = xs.iter().enumerate();
171 while let Some((i, &x)) = it.nth(0) {
175 let mut it = xs.iter().enumerate();
176 while let Some((i, &x)) = it.nth(1) {
180 let (i, &x) = xs.iter().enumerate().nth(3).unwrap();
186 fn test_iterator_enumerate_count() {
187 let xs = [0, 1, 2, 3, 4, 5];
188 assert_eq!(xs.iter().count(), 6);
192 fn test_iterator_filter_count() {
193 let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8];
194 assert_eq!(xs.iter().filter(|&&x| x % 2 == 0).count(), 5);
198 fn test_iterator_peekable() {
199 let xs = vec![0, 1, 2, 3, 4, 5];
200 let mut it = xs.iter().cloned().peekable();
202 assert_eq!(it.len(), 6);
203 assert_eq!(it.peek().unwrap(), &0);
204 assert_eq!(it.len(), 6);
205 assert_eq!(it.next().unwrap(), 0);
206 assert_eq!(it.len(), 5);
207 assert_eq!(it.next().unwrap(), 1);
208 assert_eq!(it.len(), 4);
209 assert_eq!(it.next().unwrap(), 2);
210 assert_eq!(it.len(), 3);
211 assert_eq!(it.peek().unwrap(), &3);
212 assert_eq!(it.len(), 3);
213 assert_eq!(it.peek().unwrap(), &3);
214 assert_eq!(it.len(), 3);
215 assert_eq!(it.next().unwrap(), 3);
216 assert_eq!(it.len(), 2);
217 assert_eq!(it.next().unwrap(), 4);
218 assert_eq!(it.len(), 1);
219 assert_eq!(it.peek().unwrap(), &5);
220 assert_eq!(it.len(), 1);
221 assert_eq!(it.next().unwrap(), 5);
222 assert_eq!(it.len(), 0);
223 assert!(it.peek().is_none());
224 assert_eq!(it.len(), 0);
225 assert!(it.next().is_none());
226 assert_eq!(it.len(), 0);
230 fn test_iterator_peekable_count() {
231 let xs = [0, 1, 2, 3, 4, 5];
233 let zs: [i32; 0] = [];
235 assert_eq!(xs.iter().peekable().count(), 6);
237 let mut it = xs.iter().peekable();
238 assert_eq!(it.peek(), Some(&&0));
239 assert_eq!(it.count(), 6);
241 assert_eq!(ys.iter().peekable().count(), 1);
243 let mut it = ys.iter().peekable();
244 assert_eq!(it.peek(), Some(&&10));
245 assert_eq!(it.count(), 1);
247 assert_eq!(zs.iter().peekable().count(), 0);
249 let mut it = zs.iter().peekable();
250 assert_eq!(it.peek(), None);
255 fn test_iterator_peekable_nth() {
256 let xs = [0, 1, 2, 3, 4, 5];
257 let mut it = xs.iter().peekable();
259 assert_eq!(it.peek(), Some(&&0));
260 assert_eq!(it.nth(0), Some(&0));
261 assert_eq!(it.peek(), Some(&&1));
262 assert_eq!(it.nth(1), Some(&2));
263 assert_eq!(it.peek(), Some(&&3));
264 assert_eq!(it.nth(2), Some(&5));
265 assert_eq!(it.next(), None);
269 fn test_iterator_peekable_last() {
270 let xs = [0, 1, 2, 3, 4, 5];
273 let mut it = xs.iter().peekable();
274 assert_eq!(it.peek(), Some(&&0));
275 assert_eq!(it.last(), Some(&5));
277 let mut it = ys.iter().peekable();
278 assert_eq!(it.peek(), Some(&&0));
279 assert_eq!(it.last(), Some(&0));
281 let mut it = ys.iter().peekable();
282 assert_eq!(it.next(), Some(&0));
283 assert_eq!(it.peek(), None);
284 assert_eq!(it.last(), None);
287 /// This is an iterator that follows the Iterator contract,
288 /// but it is not fused. After having returned None once, it will start
289 /// producing elements if .next() is called again.
290 pub struct CycleIter<'a, T: 'a> {
295 pub fn cycle<T>(data: &[T]) -> CycleIter<T> {
302 impl<'a, T> Iterator for CycleIter<'a, T> {
304 fn next(&mut self) -> Option<Self::Item> {
305 let elt = self.data.get(self.index);
307 self.index %= 1 + self.data.len();
313 fn test_iterator_peekable_remember_peek_none_1() {
314 // Check that the loop using .peek() terminates
315 let data = [1, 2, 3];
316 let mut iter = cycle(&data).peekable();
319 while let Some(_) = iter.next() {
320 let is_the_last = iter.peek().is_none();
321 assert_eq!(is_the_last, n == data.len() - 1);
323 if n > data.len() { break; }
325 assert_eq!(n, data.len());
329 fn test_iterator_peekable_remember_peek_none_2() {
331 let mut iter = cycle(&data).peekable();
333 assert_eq!(iter.peek(), None);
334 assert_eq!(iter.last(), None);
338 fn test_iterator_peekable_remember_peek_none_3() {
340 let mut iter = cycle(&data).peekable();
342 assert_eq!(iter.nth(0), Some(&0));
344 let mut iter = cycle(&data).peekable();
346 assert_eq!(iter.peek(), None);
347 assert_eq!(iter.nth(0), None);
351 fn test_iterator_take_while() {
352 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
353 let ys = [0, 1, 2, 3, 5, 13];
354 let it = xs.iter().take_while(|&x| *x < 15);
357 assert_eq!(*x, ys[i]);
360 assert_eq!(i, ys.len());
364 fn test_iterator_skip_while() {
365 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
366 let ys = [15, 16, 17, 19];
367 let it = xs.iter().skip_while(|&x| *x < 15);
370 assert_eq!(*x, ys[i]);
373 assert_eq!(i, ys.len());
377 fn test_iterator_skip() {
378 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
379 let ys = [13, 15, 16, 17, 19, 20, 30];
380 let mut it = xs.iter().skip(5);
382 while let Some(&x) = it.next() {
383 assert_eq!(x, ys[i]);
385 assert_eq!(it.len(), xs.len()-5-i);
387 assert_eq!(i, ys.len());
388 assert_eq!(it.len(), 0);
392 fn test_iterator_skip_doubleended() {
393 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
394 let mut it = xs.iter().rev().skip(5);
395 assert_eq!(it.next(), Some(&15));
396 assert_eq!(it.by_ref().rev().next(), Some(&0));
397 assert_eq!(it.next(), Some(&13));
398 assert_eq!(it.by_ref().rev().next(), Some(&1));
399 assert_eq!(it.next(), Some(&5));
400 assert_eq!(it.by_ref().rev().next(), Some(&2));
401 assert_eq!(it.next(), Some(&3));
402 assert_eq!(it.next(), None);
403 let mut it = xs.iter().rev().skip(5).rev();
404 assert_eq!(it.next(), Some(&0));
405 assert_eq!(it.rev().next(), Some(&15));
406 let mut it_base = xs.iter();
408 let mut it = it_base.by_ref().skip(5).rev();
409 assert_eq!(it.next(), Some(&30));
410 assert_eq!(it.next(), Some(&20));
411 assert_eq!(it.next(), Some(&19));
412 assert_eq!(it.next(), Some(&17));
413 assert_eq!(it.next(), Some(&16));
414 assert_eq!(it.next(), Some(&15));
415 assert_eq!(it.next(), Some(&13));
416 assert_eq!(it.next(), None);
418 // make sure the skipped parts have not been consumed
419 assert_eq!(it_base.next(), Some(&0));
420 assert_eq!(it_base.next(), Some(&1));
421 assert_eq!(it_base.next(), Some(&2));
422 assert_eq!(it_base.next(), Some(&3));
423 assert_eq!(it_base.next(), Some(&5));
424 assert_eq!(it_base.next(), None);
425 let it = xs.iter().skip(5).rev();
426 assert_eq!(it.last(), Some(&13));
430 fn test_iterator_skip_nth() {
431 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
433 let mut it = xs.iter().skip(0);
434 assert_eq!(it.nth(0), Some(&0));
435 assert_eq!(it.nth(1), Some(&2));
437 let mut it = xs.iter().skip(5);
438 assert_eq!(it.nth(0), Some(&13));
439 assert_eq!(it.nth(1), Some(&16));
441 let mut it = xs.iter().skip(12);
442 assert_eq!(it.nth(0), None);
447 fn test_iterator_skip_count() {
448 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
450 assert_eq!(xs.iter().skip(0).count(), 12);
451 assert_eq!(xs.iter().skip(1).count(), 11);
452 assert_eq!(xs.iter().skip(11).count(), 1);
453 assert_eq!(xs.iter().skip(12).count(), 0);
454 assert_eq!(xs.iter().skip(13).count(), 0);
458 fn test_iterator_skip_last() {
459 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
461 assert_eq!(xs.iter().skip(0).last(), Some(&30));
462 assert_eq!(xs.iter().skip(1).last(), Some(&30));
463 assert_eq!(xs.iter().skip(11).last(), Some(&30));
464 assert_eq!(xs.iter().skip(12).last(), None);
465 assert_eq!(xs.iter().skip(13).last(), None);
467 let mut it = xs.iter().skip(5);
468 assert_eq!(it.next(), Some(&13));
469 assert_eq!(it.last(), Some(&30));
473 fn test_iterator_take() {
474 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
475 let ys = [0, 1, 2, 3, 5];
476 let mut it = xs.iter().take(5);
478 assert_eq!(it.len(), 5);
479 while let Some(&x) = it.next() {
480 assert_eq!(x, ys[i]);
482 assert_eq!(it.len(), 5-i);
484 assert_eq!(i, ys.len());
485 assert_eq!(it.len(), 0);
489 fn test_iterator_take_nth() {
490 let xs = [0, 1, 2, 4, 5];
491 let mut it = xs.iter();
493 let mut take = it.by_ref().take(3);
495 while let Some(&x) = take.nth(0) {
500 assert_eq!(it.nth(1), Some(&5));
501 assert_eq!(it.nth(0), None);
503 let xs = [0, 1, 2, 3, 4];
504 let mut it = xs.iter().take(7);
506 while let Some(&x) = it.nth(1) {
513 fn test_iterator_take_short() {
514 let xs = [0, 1, 2, 3];
515 let ys = [0, 1, 2, 3];
516 let mut it = xs.iter().take(5);
518 assert_eq!(it.len(), 4);
519 while let Some(&x) = it.next() {
520 assert_eq!(x, ys[i]);
522 assert_eq!(it.len(), 4-i);
524 assert_eq!(i, ys.len());
525 assert_eq!(it.len(), 0);
529 fn test_iterator_scan() {
530 // test the type inference
531 fn add(old: &mut isize, new: &usize) -> Option<f64> {
532 *old += *new as isize;
535 let xs = [0, 1, 2, 3, 4];
536 let ys = [0f64, 1.0, 3.0, 6.0, 10.0];
538 let it = xs.iter().scan(0, add);
541 assert_eq!(x, ys[i]);
544 assert_eq!(i, ys.len());
548 fn test_iterator_flat_map() {
550 let ys = [0, 1, 2, 3, 4, 5, 6, 7, 8];
551 let it = xs.iter().flat_map(|&x| (x..).step_by(1).take(3));
554 assert_eq!(x, ys[i]);
557 assert_eq!(i, ys.len());
562 let xs = [1, 2, 3, 4];
568 .collect::<Vec<usize>>();
570 assert_eq!(n, xs.len());
571 assert_eq!(&xs[..], &ys[..]);
577 let it = (0..).step_by(1).take(cycle_len).cycle();
578 assert_eq!(it.size_hint(), (usize::MAX, None));
579 for (i, x) in it.take(100).enumerate() {
580 assert_eq!(i % cycle_len, x);
583 let mut it = (0..).step_by(1).take(0).cycle();
584 assert_eq!(it.size_hint(), (0, Some(0)));
585 assert_eq!(it.next(), None);
589 fn test_iterator_nth() {
590 let v: &[_] = &[0, 1, 2, 3, 4];
591 for i in 0..v.len() {
592 assert_eq!(v.iter().nth(i).unwrap(), &v[i]);
594 assert_eq!(v.iter().nth(v.len()), None);
598 fn test_iterator_last() {
599 let v: &[_] = &[0, 1, 2, 3, 4];
600 assert_eq!(v.iter().last().unwrap(), &4);
601 assert_eq!(v[..1].iter().last().unwrap(), &0);
605 fn test_iterator_len() {
606 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
607 assert_eq!(v[..4].iter().count(), 4);
608 assert_eq!(v[..10].iter().count(), 10);
609 assert_eq!(v[..0].iter().count(), 0);
613 fn test_iterator_sum() {
614 let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
615 assert_eq!(v[..4].iter().cloned().sum::<i32>(), 6);
616 assert_eq!(v.iter().cloned().sum::<i32>(), 55);
617 assert_eq!(v[..0].iter().cloned().sum::<i32>(), 0);
621 fn test_iterator_sum_result() {
622 let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)];
623 assert_eq!(v.iter().cloned().sum::<Result<i32, _>>(), Ok(10));
624 let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)];
625 assert_eq!(v.iter().cloned().sum::<Result<i32, _>>(), Err(()));
629 fn test_iterator_product() {
630 let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
631 assert_eq!(v[..4].iter().cloned().product::<i32>(), 0);
632 assert_eq!(v[1..5].iter().cloned().product::<i32>(), 24);
633 assert_eq!(v[..0].iter().cloned().product::<i32>(), 1);
637 fn test_iterator_product_result() {
638 let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)];
639 assert_eq!(v.iter().cloned().product::<Result<i32, _>>(), Ok(24));
640 let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)];
641 assert_eq!(v.iter().cloned().product::<Result<i32, _>>(), Err(()));
645 fn test_iterator_max() {
646 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
647 assert_eq!(v[..4].iter().cloned().max(), Some(3));
648 assert_eq!(v.iter().cloned().max(), Some(10));
649 assert_eq!(v[..0].iter().cloned().max(), None);
653 fn test_iterator_min() {
654 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
655 assert_eq!(v[..4].iter().cloned().min(), Some(0));
656 assert_eq!(v.iter().cloned().min(), Some(0));
657 assert_eq!(v[..0].iter().cloned().min(), None);
661 fn test_iterator_size_hint() {
662 let c = (0..).step_by(1);
663 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
664 let v2 = &[10, 11, 12];
667 assert_eq!(c.size_hint(), (usize::MAX, None));
668 assert_eq!(vi.clone().size_hint(), (10, Some(10)));
670 assert_eq!(c.clone().take(5).size_hint(), (5, Some(5)));
671 assert_eq!(c.clone().skip(5).size_hint().1, None);
672 assert_eq!(c.clone().take_while(|_| false).size_hint(), (0, None));
673 assert_eq!(c.clone().skip_while(|_| false).size_hint(), (0, None));
674 assert_eq!(c.clone().enumerate().size_hint(), (usize::MAX, None));
675 assert_eq!(c.clone().chain(vi.clone().cloned()).size_hint(), (usize::MAX, None));
676 assert_eq!(c.clone().zip(vi.clone()).size_hint(), (10, Some(10)));
677 assert_eq!(c.clone().scan(0, |_,_| Some(0)).size_hint(), (0, None));
678 assert_eq!(c.clone().filter(|_| false).size_hint(), (0, None));
679 assert_eq!(c.clone().map(|_| 0).size_hint(), (usize::MAX, None));
680 assert_eq!(c.filter_map(|_| Some(0)).size_hint(), (0, None));
682 assert_eq!(vi.clone().take(5).size_hint(), (5, Some(5)));
683 assert_eq!(vi.clone().take(12).size_hint(), (10, Some(10)));
684 assert_eq!(vi.clone().skip(3).size_hint(), (7, Some(7)));
685 assert_eq!(vi.clone().skip(12).size_hint(), (0, Some(0)));
686 assert_eq!(vi.clone().take_while(|_| false).size_hint(), (0, Some(10)));
687 assert_eq!(vi.clone().skip_while(|_| false).size_hint(), (0, Some(10)));
688 assert_eq!(vi.clone().enumerate().size_hint(), (10, Some(10)));
689 assert_eq!(vi.clone().chain(v2).size_hint(), (13, Some(13)));
690 assert_eq!(vi.clone().zip(v2).size_hint(), (3, Some(3)));
691 assert_eq!(vi.clone().scan(0, |_,_| Some(0)).size_hint(), (0, Some(10)));
692 assert_eq!(vi.clone().filter(|_| false).size_hint(), (0, Some(10)));
693 assert_eq!(vi.clone().map(|&i| i+1).size_hint(), (10, Some(10)));
694 assert_eq!(vi.filter_map(|_| Some(0)).size_hint(), (0, Some(10)));
699 let a = vec![1, 2, 3, 4, 5];
700 let b: Vec<isize> = a.iter().cloned().collect();
706 let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
707 assert!(v.iter().all(|&x| x < 10));
708 assert!(!v.iter().all(|&x| x % 2 == 0));
709 assert!(!v.iter().all(|&x| x > 100));
710 assert!(v[..0].iter().all(|_| panic!()));
715 let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
716 assert!(v.iter().any(|&x| x < 10));
717 assert!(v.iter().any(|&x| x % 2 == 0));
718 assert!(!v.iter().any(|&x| x > 100));
719 assert!(!v[..0].iter().any(|_| panic!()));
724 let v: &[isize] = &[1, 3, 9, 27, 103, 14, 11];
725 assert_eq!(*v.iter().find(|&&x| x & 1 == 0).unwrap(), 14);
726 assert_eq!(*v.iter().find(|&&x| x % 3 == 0).unwrap(), 3);
727 assert!(v.iter().find(|&&x| x % 12 == 0).is_none());
732 let v = &[1, 3, 9, 27, 103, 14, 11];
733 assert_eq!(v.iter().position(|x| *x & 1 == 0).unwrap(), 5);
734 assert_eq!(v.iter().position(|x| *x % 3 == 0).unwrap(), 1);
735 assert!(v.iter().position(|x| *x % 12 == 0).is_none());
740 let xs = &[1, 2, 2, 1, 5, 9, 0, 2];
741 assert_eq!(xs.iter().filter(|x| **x == 2).count(), 3);
742 assert_eq!(xs.iter().filter(|x| **x == 5).count(), 1);
743 assert_eq!(xs.iter().filter(|x| **x == 95).count(), 0);
747 fn test_max_by_key() {
748 let xs: &[isize] = &[-3, 0, 1, 5, -10];
749 assert_eq!(*xs.iter().max_by_key(|x| x.abs()).unwrap(), -10);
754 let xs: &[isize] = &[-3, 0, 1, 5, -10];
755 assert_eq!(*xs.iter().max_by(|x, y| x.abs().cmp(&y.abs())).unwrap(), -10);
759 fn test_min_by_key() {
760 let xs: &[isize] = &[-3, 0, 1, 5, -10];
761 assert_eq!(*xs.iter().min_by_key(|x| x.abs()).unwrap(), 0);
766 let xs: &[isize] = &[-3, 0, 1, 5, -10];
767 assert_eq!(*xs.iter().min_by(|x, y| x.abs().cmp(&y.abs())).unwrap(), 0);
773 // sum the first five values
774 let partial_sum = xs.by_ref().take(5).fold(0, |a, b| a + b);
775 assert_eq!(partial_sum, 10);
776 assert_eq!(xs.next(), Some(5));
781 let xs = [2, 4, 6, 8, 10, 12, 14, 16];
782 let mut it = xs.iter();
785 assert!(it.rev().cloned().collect::<Vec<isize>>() ==
786 vec![16, 14, 12, 10, 8, 6]);
791 let xs = [2, 4, 6, 8];
793 let mut it = xs.iter().cloned();
794 assert_eq!(it.len(), 4);
795 assert_eq!(it.next(), Some(2));
796 assert_eq!(it.len(), 3);
797 assert_eq!(it.next(), Some(4));
798 assert_eq!(it.len(), 2);
799 assert_eq!(it.next_back(), Some(8));
800 assert_eq!(it.len(), 1);
801 assert_eq!(it.next_back(), Some(6));
802 assert_eq!(it.len(), 0);
803 assert_eq!(it.next_back(), None);
807 fn test_double_ended_map() {
808 let xs = [1, 2, 3, 4, 5, 6];
809 let mut it = xs.iter().map(|&x| x * -1);
810 assert_eq!(it.next(), Some(-1));
811 assert_eq!(it.next(), Some(-2));
812 assert_eq!(it.next_back(), Some(-6));
813 assert_eq!(it.next_back(), Some(-5));
814 assert_eq!(it.next(), Some(-3));
815 assert_eq!(it.next_back(), Some(-4));
816 assert_eq!(it.next(), None);
820 fn test_double_ended_enumerate() {
821 let xs = [1, 2, 3, 4, 5, 6];
822 let mut it = xs.iter().cloned().enumerate();
823 assert_eq!(it.next(), Some((0, 1)));
824 assert_eq!(it.next(), Some((1, 2)));
825 assert_eq!(it.next_back(), Some((5, 6)));
826 assert_eq!(it.next_back(), Some((4, 5)));
827 assert_eq!(it.next_back(), Some((3, 4)));
828 assert_eq!(it.next_back(), Some((2, 3)));
829 assert_eq!(it.next(), None);
833 fn test_double_ended_zip() {
834 let xs = [1, 2, 3, 4, 5, 6];
835 let ys = [1, 2, 3, 7];
836 let a = xs.iter().cloned();
837 let b = ys.iter().cloned();
838 let mut it = a.zip(b);
839 assert_eq!(it.next(), Some((1, 1)));
840 assert_eq!(it.next(), Some((2, 2)));
841 assert_eq!(it.next_back(), Some((4, 7)));
842 assert_eq!(it.next_back(), Some((3, 3)));
843 assert_eq!(it.next(), None);
847 fn test_double_ended_filter() {
848 let xs = [1, 2, 3, 4, 5, 6];
849 let mut it = xs.iter().filter(|&x| *x & 1 == 0);
850 assert_eq!(it.next_back().unwrap(), &6);
851 assert_eq!(it.next_back().unwrap(), &4);
852 assert_eq!(it.next().unwrap(), &2);
853 assert_eq!(it.next_back(), None);
857 fn test_double_ended_filter_map() {
858 let xs = [1, 2, 3, 4, 5, 6];
859 let mut it = xs.iter().filter_map(|&x| if x & 1 == 0 { Some(x * 2) } else { None });
860 assert_eq!(it.next_back().unwrap(), 12);
861 assert_eq!(it.next_back().unwrap(), 8);
862 assert_eq!(it.next().unwrap(), 4);
863 assert_eq!(it.next_back(), None);
867 fn test_double_ended_chain() {
868 let xs = [1, 2, 3, 4, 5];
870 let mut it = xs.iter().chain(&ys).rev();
871 assert_eq!(it.next().unwrap(), &11);
872 assert_eq!(it.next().unwrap(), &9);
873 assert_eq!(it.next_back().unwrap(), &1);
874 assert_eq!(it.next_back().unwrap(), &2);
875 assert_eq!(it.next_back().unwrap(), &3);
876 assert_eq!(it.next_back().unwrap(), &4);
877 assert_eq!(it.next_back().unwrap(), &5);
878 assert_eq!(it.next_back().unwrap(), &7);
879 assert_eq!(it.next_back(), None);
882 // test that .chain() is well behaved with an unfused iterator
883 struct CrazyIterator(bool);
884 impl CrazyIterator { fn new() -> CrazyIterator { CrazyIterator(false) } }
885 impl Iterator for CrazyIterator {
887 fn next(&mut self) -> Option<i32> {
888 if self.0 { Some(99) } else { self.0 = true; None }
892 impl DoubleEndedIterator for CrazyIterator {
893 fn next_back(&mut self) -> Option<i32> {
898 assert_eq!(CrazyIterator::new().chain(0..10).rev().last(), Some(0));
899 assert!((0..10).chain(CrazyIterator::new()).rev().any(|i| i == 0));
903 fn test_rposition() {
904 fn f(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'b' }
905 fn g(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'd' }
906 let v = [(0, 'a'), (1, 'b'), (2, 'c'), (3, 'b')];
908 assert_eq!(v.iter().rposition(f), Some(3));
909 assert!(v.iter().rposition(g).is_none());
914 fn test_rposition_panic() {
915 let v: [(Box<_>, Box<_>); 4] =
916 [(box 0, box 0), (box 0, box 0),
917 (box 0, box 0), (box 0, box 0)];
919 v.iter().rposition(|_elt| {
930 fn test_double_ended_flat_map() {
933 let mut it = u.iter().flat_map(|x| &v[*x..v.len()]);
934 assert_eq!(it.next_back().unwrap(), &8);
935 assert_eq!(it.next().unwrap(), &5);
936 assert_eq!(it.next_back().unwrap(), &7);
937 assert_eq!(it.next_back().unwrap(), &6);
938 assert_eq!(it.next_back().unwrap(), &8);
939 assert_eq!(it.next().unwrap(), &6);
940 assert_eq!(it.next_back().unwrap(), &7);
941 assert_eq!(it.next_back(), None);
942 assert_eq!(it.next(), None);
943 assert_eq!(it.next_back(), None);
947 fn test_double_ended_range() {
948 assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]);
949 for _ in (10..0).rev() {
950 panic!("unreachable");
953 assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]);
954 for _ in (10..0).rev() {
955 panic!("unreachable");
961 assert_eq!((0..5).collect::<Vec<_>>(), [0, 1, 2, 3, 4]);
962 assert_eq!((-10..-1).collect::<Vec<_>>(), [-10, -9, -8, -7, -6, -5, -4, -3, -2]);
963 assert_eq!((0..5).rev().collect::<Vec<_>>(), [4, 3, 2, 1, 0]);
964 assert_eq!((200..-5).count(), 0);
965 assert_eq!((200..-5).rev().count(), 0);
966 assert_eq!((200..200).count(), 0);
967 assert_eq!((200..200).rev().count(), 0);
969 assert_eq!((0..100).size_hint(), (100, Some(100)));
970 // this test is only meaningful when sizeof usize < sizeof u64
971 assert_eq!((usize::MAX - 1..usize::MAX).size_hint(), (1, Some(1)));
972 assert_eq!((-10..-1).size_hint(), (9, Some(9)));
973 assert_eq!((-1..-10).size_hint(), (0, Some(0)));
975 assert_eq!((-70..58).size_hint(), (128, Some(128)));
976 assert_eq!((-128..127).size_hint(), (255, Some(255)));
977 assert_eq!((-2..isize::MAX).size_hint(),
978 (isize::MAX as usize + 2, Some(isize::MAX as usize + 2)));
982 fn test_range_step() {
983 assert_eq!((0..20).step_by(5).collect::<Vec<isize>>(), [0, 5, 10, 15]);
984 assert_eq!((20..0).step_by(-5).collect::<Vec<isize>>(), [20, 15, 10, 5]);
985 assert_eq!((20..0).step_by(-6).collect::<Vec<isize>>(), [20, 14, 8, 2]);
986 assert_eq!((200..255).step_by(50).collect::<Vec<u8>>(), [200, 250]);
987 assert_eq!((200..-5).step_by(1).collect::<Vec<isize>>(), []);
988 assert_eq!((200..200).step_by(1).collect::<Vec<isize>>(), []);
990 assert_eq!((0..20).step_by(1).size_hint(), (20, Some(20)));
991 assert_eq!((0..20).step_by(21).size_hint(), (1, Some(1)));
992 assert_eq!((0..20).step_by(5).size_hint(), (4, Some(4)));
993 assert_eq!((20..0).step_by(-5).size_hint(), (4, Some(4)));
994 assert_eq!((20..0).step_by(-6).size_hint(), (4, Some(4)));
995 assert_eq!((20..-5).step_by(1).size_hint(), (0, Some(0)));
996 assert_eq!((20..20).step_by(1).size_hint(), (0, Some(0)));
997 assert_eq!((0..1).step_by(0).size_hint(), (0, None));
998 assert_eq!((i8::MAX..i8::MIN).step_by(i8::MIN).size_hint(), (2, Some(2)));
999 assert_eq!((i16::MIN..i16::MAX).step_by(i16::MAX).size_hint(), (3, Some(3)));
1000 assert_eq!((isize::MIN..isize::MAX).step_by(1).size_hint(), (usize::MAX, Some(usize::MAX)));
1005 let mut it = repeat(42);
1006 assert_eq!(it.next(), Some(42));
1007 assert_eq!(it.next(), Some(42));
1008 assert_eq!(it.next(), Some(42));
1014 assert_eq!(it.len(), 3);
1015 assert_eq!(it.next(), Some(0));
1016 assert_eq!(it.len(), 2);
1017 assert_eq!(it.next(), Some(1));
1018 assert_eq!(it.len(), 1);
1019 assert_eq!(it.next(), Some(2));
1020 assert_eq!(it.len(), 0);
1021 assert_eq!(it.next(), None);
1022 assert_eq!(it.len(), 0);
1023 assert_eq!(it.next(), None);
1024 assert_eq!(it.len(), 0);
1025 assert_eq!(it.next(), None);
1026 assert_eq!(it.len(), 0);
1030 fn test_fuse_nth() {
1032 let mut it = xs.iter();
1034 assert_eq!(it.len(), 3);
1035 assert_eq!(it.nth(2), Some(&2));
1036 assert_eq!(it.len(), 0);
1037 assert_eq!(it.nth(2), None);
1038 assert_eq!(it.len(), 0);
1042 fn test_fuse_last() {
1046 assert_eq!(it.len(), 3);
1047 assert_eq!(it.last(), Some(&2));
1051 fn test_fuse_count() {
1055 assert_eq!(it.len(), 3);
1056 assert_eq!(it.count(), 3);
1057 // Can't check len now because count consumes.
1062 let mut it = once(42);
1063 assert_eq!(it.next(), Some(42));
1064 assert_eq!(it.next(), None);
1069 let mut it = empty::<i32>();
1070 assert_eq!(it.next(), None);
1074 fn test_chain_fold() {
1078 let mut iter = xs.iter().chain(&ys);
1080 let mut result = Vec::new();
1081 iter.fold((), |(), &elt| result.push(elt));
1082 assert_eq!(&[2, 3, 1, 2, 0], &result[..]);
1086 fn test_step_replace_unsigned() {
1088 let y = x.replace_zero();
1093 let y = x.replace_one();
1099 fn test_step_replace_signed() {
1101 let y = x.replace_zero();
1106 let y = x.replace_one();
1112 fn test_step_replace_no_between() {
1114 let y = x.replace_zero();
1119 let y = x.replace_one();