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_iterator_step_by() {
150 // Replace with (0..).step_by(1) after Range::step_by gets removed
151 let mut it = Iterator::step_by((0..), 1).take(3);
152 assert_eq!(it.next(), Some(0));
153 assert_eq!(it.next(), Some(1));
154 assert_eq!(it.next(), Some(2));
155 assert_eq!(it.next(), None);
157 // Replace with (0..).step_by(3) after Range::step_by gets removed
158 let mut it = Iterator::step_by((0..), 3).take(4);
159 assert_eq!(it.next(), Some(0));
160 assert_eq!(it.next(), Some(3));
161 assert_eq!(it.next(), Some(6));
162 assert_eq!(it.next(), Some(9));
163 assert_eq!(it.next(), None);
168 fn test_iterator_step_by_zero() {
169 // Replace with (0..).step_by(0) after Range::step_by gets removed
170 let mut it = Iterator::step_by((0..), 0);
175 fn test_iterator_step_by_size_hint() {
176 struct StubSizeHint(usize, Option<usize>);
177 impl Iterator for StubSizeHint {
179 fn next(&mut self) -> Option<()> {
181 if let Some(ref mut upper) = self.1 {
186 fn size_hint(&self) -> (usize, Option<usize>) {
191 // The two checks in each case are needed because the logic
192 // is different before the first call to `next()`.
194 let mut it = StubSizeHint(10, Some(10)).step_by(1);
195 assert_eq!(it.size_hint(), (10, Some(10)));
197 assert_eq!(it.size_hint(), (9, Some(9)));
200 let mut it = StubSizeHint(10, Some(10)).step_by(3);
201 assert_eq!(it.size_hint(), (4, Some(4)));
203 assert_eq!(it.size_hint(), (3, Some(3)));
205 // larger base range, but not enough to get another element
206 let mut it = StubSizeHint(12, Some(12)).step_by(3);
207 assert_eq!(it.size_hint(), (4, Some(4)));
209 assert_eq!(it.size_hint(), (3, Some(3)));
211 // smaller base range, so fewer resulting elements
212 let mut it = StubSizeHint(9, Some(9)).step_by(3);
213 assert_eq!(it.size_hint(), (3, Some(3)));
215 assert_eq!(it.size_hint(), (2, Some(2)));
217 // infinite upper bound
218 let mut it = StubSizeHint(usize::MAX, None).step_by(1);
219 assert_eq!(it.size_hint(), (usize::MAX, None));
221 assert_eq!(it.size_hint(), (usize::MAX-1, None));
223 // still infinite with larger step
224 let mut it = StubSizeHint(7, None).step_by(3);
225 assert_eq!(it.size_hint(), (3, None));
227 assert_eq!(it.size_hint(), (2, None));
229 // propagates ExactSizeIterator
231 let it = a.iter().step_by(2);
232 assert_eq!(it.len(), 3);
234 // Cannot be TrustedLen as a step greater than one makes an iterator
235 // with (usize::MAX, None) no longer meet the safety requirements
236 trait TrustedLenCheck { fn test(self) -> bool; }
237 impl<T:Iterator> TrustedLenCheck for T {
238 default fn test(self) -> bool { false }
240 impl<T:TrustedLen> TrustedLenCheck for T {
241 fn test(self) -> bool { true }
243 assert!(TrustedLenCheck::test(a.iter()));
244 assert!(!TrustedLenCheck::test(a.iter().step_by(1)));
248 fn test_filter_map() {
249 let it = (0..).step_by(1).take(10)
250 .filter_map(|x| if x % 2 == 0 { Some(x*x) } else { None });
251 assert_eq!(it.collect::<Vec<usize>>(), [0*0, 2*2, 4*4, 6*6, 8*8]);
255 fn test_iterator_enumerate() {
256 let xs = [0, 1, 2, 3, 4, 5];
257 let it = xs.iter().enumerate();
264 fn test_iterator_enumerate_nth() {
265 let xs = [0, 1, 2, 3, 4, 5];
266 for (i, &x) in xs.iter().enumerate() {
270 let mut it = xs.iter().enumerate();
271 while let Some((i, &x)) = it.nth(0) {
275 let mut it = xs.iter().enumerate();
276 while let Some((i, &x)) = it.nth(1) {
280 let (i, &x) = xs.iter().enumerate().nth(3).unwrap();
286 fn test_iterator_enumerate_count() {
287 let xs = [0, 1, 2, 3, 4, 5];
288 assert_eq!(xs.iter().count(), 6);
292 fn test_iterator_filter_count() {
293 let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8];
294 assert_eq!(xs.iter().filter(|&&x| x % 2 == 0).count(), 5);
298 fn test_iterator_peekable() {
299 let xs = vec![0, 1, 2, 3, 4, 5];
300 let mut it = xs.iter().cloned().peekable();
302 assert_eq!(it.len(), 6);
303 assert_eq!(it.peek().unwrap(), &0);
304 assert_eq!(it.len(), 6);
305 assert_eq!(it.next().unwrap(), 0);
306 assert_eq!(it.len(), 5);
307 assert_eq!(it.next().unwrap(), 1);
308 assert_eq!(it.len(), 4);
309 assert_eq!(it.next().unwrap(), 2);
310 assert_eq!(it.len(), 3);
311 assert_eq!(it.peek().unwrap(), &3);
312 assert_eq!(it.len(), 3);
313 assert_eq!(it.peek().unwrap(), &3);
314 assert_eq!(it.len(), 3);
315 assert_eq!(it.next().unwrap(), 3);
316 assert_eq!(it.len(), 2);
317 assert_eq!(it.next().unwrap(), 4);
318 assert_eq!(it.len(), 1);
319 assert_eq!(it.peek().unwrap(), &5);
320 assert_eq!(it.len(), 1);
321 assert_eq!(it.next().unwrap(), 5);
322 assert_eq!(it.len(), 0);
323 assert!(it.peek().is_none());
324 assert_eq!(it.len(), 0);
325 assert!(it.next().is_none());
326 assert_eq!(it.len(), 0);
330 fn test_iterator_peekable_count() {
331 let xs = [0, 1, 2, 3, 4, 5];
333 let zs: [i32; 0] = [];
335 assert_eq!(xs.iter().peekable().count(), 6);
337 let mut it = xs.iter().peekable();
338 assert_eq!(it.peek(), Some(&&0));
339 assert_eq!(it.count(), 6);
341 assert_eq!(ys.iter().peekable().count(), 1);
343 let mut it = ys.iter().peekable();
344 assert_eq!(it.peek(), Some(&&10));
345 assert_eq!(it.count(), 1);
347 assert_eq!(zs.iter().peekable().count(), 0);
349 let mut it = zs.iter().peekable();
350 assert_eq!(it.peek(), None);
355 fn test_iterator_peekable_nth() {
356 let xs = [0, 1, 2, 3, 4, 5];
357 let mut it = xs.iter().peekable();
359 assert_eq!(it.peek(), Some(&&0));
360 assert_eq!(it.nth(0), Some(&0));
361 assert_eq!(it.peek(), Some(&&1));
362 assert_eq!(it.nth(1), Some(&2));
363 assert_eq!(it.peek(), Some(&&3));
364 assert_eq!(it.nth(2), Some(&5));
365 assert_eq!(it.next(), None);
369 fn test_iterator_peekable_last() {
370 let xs = [0, 1, 2, 3, 4, 5];
373 let mut it = xs.iter().peekable();
374 assert_eq!(it.peek(), Some(&&0));
375 assert_eq!(it.last(), Some(&5));
377 let mut it = ys.iter().peekable();
378 assert_eq!(it.peek(), Some(&&0));
379 assert_eq!(it.last(), Some(&0));
381 let mut it = ys.iter().peekable();
382 assert_eq!(it.next(), Some(&0));
383 assert_eq!(it.peek(), None);
384 assert_eq!(it.last(), None);
387 /// This is an iterator that follows the Iterator contract,
388 /// but it is not fused. After having returned None once, it will start
389 /// producing elements if .next() is called again.
390 pub struct CycleIter<'a, T: 'a> {
395 pub fn cycle<T>(data: &[T]) -> CycleIter<T> {
402 impl<'a, T> Iterator for CycleIter<'a, T> {
404 fn next(&mut self) -> Option<Self::Item> {
405 let elt = self.data.get(self.index);
407 self.index %= 1 + self.data.len();
413 fn test_iterator_peekable_remember_peek_none_1() {
414 // Check that the loop using .peek() terminates
415 let data = [1, 2, 3];
416 let mut iter = cycle(&data).peekable();
419 while let Some(_) = iter.next() {
420 let is_the_last = iter.peek().is_none();
421 assert_eq!(is_the_last, n == data.len() - 1);
423 if n > data.len() { break; }
425 assert_eq!(n, data.len());
429 fn test_iterator_peekable_remember_peek_none_2() {
431 let mut iter = cycle(&data).peekable();
433 assert_eq!(iter.peek(), None);
434 assert_eq!(iter.last(), None);
438 fn test_iterator_peekable_remember_peek_none_3() {
440 let mut iter = cycle(&data).peekable();
442 assert_eq!(iter.nth(0), Some(&0));
444 let mut iter = cycle(&data).peekable();
446 assert_eq!(iter.peek(), None);
447 assert_eq!(iter.nth(0), None);
451 fn test_iterator_take_while() {
452 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
453 let ys = [0, 1, 2, 3, 5, 13];
454 let it = xs.iter().take_while(|&x| *x < 15);
457 assert_eq!(*x, ys[i]);
460 assert_eq!(i, ys.len());
464 fn test_iterator_skip_while() {
465 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
466 let ys = [15, 16, 17, 19];
467 let it = xs.iter().skip_while(|&x| *x < 15);
470 assert_eq!(*x, ys[i]);
473 assert_eq!(i, ys.len());
477 fn test_iterator_skip() {
478 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
479 let ys = [13, 15, 16, 17, 19, 20, 30];
480 let mut it = xs.iter().skip(5);
482 while let Some(&x) = it.next() {
483 assert_eq!(x, ys[i]);
485 assert_eq!(it.len(), xs.len()-5-i);
487 assert_eq!(i, ys.len());
488 assert_eq!(it.len(), 0);
492 fn test_iterator_skip_doubleended() {
493 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
494 let mut it = xs.iter().rev().skip(5);
495 assert_eq!(it.next(), Some(&15));
496 assert_eq!(it.by_ref().rev().next(), Some(&0));
497 assert_eq!(it.next(), Some(&13));
498 assert_eq!(it.by_ref().rev().next(), Some(&1));
499 assert_eq!(it.next(), Some(&5));
500 assert_eq!(it.by_ref().rev().next(), Some(&2));
501 assert_eq!(it.next(), Some(&3));
502 assert_eq!(it.next(), None);
503 let mut it = xs.iter().rev().skip(5).rev();
504 assert_eq!(it.next(), Some(&0));
505 assert_eq!(it.rev().next(), Some(&15));
506 let mut it_base = xs.iter();
508 let mut it = it_base.by_ref().skip(5).rev();
509 assert_eq!(it.next(), Some(&30));
510 assert_eq!(it.next(), Some(&20));
511 assert_eq!(it.next(), Some(&19));
512 assert_eq!(it.next(), Some(&17));
513 assert_eq!(it.next(), Some(&16));
514 assert_eq!(it.next(), Some(&15));
515 assert_eq!(it.next(), Some(&13));
516 assert_eq!(it.next(), None);
518 // make sure the skipped parts have not been consumed
519 assert_eq!(it_base.next(), Some(&0));
520 assert_eq!(it_base.next(), Some(&1));
521 assert_eq!(it_base.next(), Some(&2));
522 assert_eq!(it_base.next(), Some(&3));
523 assert_eq!(it_base.next(), Some(&5));
524 assert_eq!(it_base.next(), None);
525 let it = xs.iter().skip(5).rev();
526 assert_eq!(it.last(), Some(&13));
530 fn test_iterator_skip_nth() {
531 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
533 let mut it = xs.iter().skip(0);
534 assert_eq!(it.nth(0), Some(&0));
535 assert_eq!(it.nth(1), Some(&2));
537 let mut it = xs.iter().skip(5);
538 assert_eq!(it.nth(0), Some(&13));
539 assert_eq!(it.nth(1), Some(&16));
541 let mut it = xs.iter().skip(12);
542 assert_eq!(it.nth(0), None);
547 fn test_iterator_skip_count() {
548 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
550 assert_eq!(xs.iter().skip(0).count(), 12);
551 assert_eq!(xs.iter().skip(1).count(), 11);
552 assert_eq!(xs.iter().skip(11).count(), 1);
553 assert_eq!(xs.iter().skip(12).count(), 0);
554 assert_eq!(xs.iter().skip(13).count(), 0);
558 fn test_iterator_skip_last() {
559 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
561 assert_eq!(xs.iter().skip(0).last(), Some(&30));
562 assert_eq!(xs.iter().skip(1).last(), Some(&30));
563 assert_eq!(xs.iter().skip(11).last(), Some(&30));
564 assert_eq!(xs.iter().skip(12).last(), None);
565 assert_eq!(xs.iter().skip(13).last(), None);
567 let mut it = xs.iter().skip(5);
568 assert_eq!(it.next(), Some(&13));
569 assert_eq!(it.last(), Some(&30));
573 fn test_iterator_take() {
574 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
575 let ys = [0, 1, 2, 3, 5];
576 let mut it = xs.iter().take(5);
578 assert_eq!(it.len(), 5);
579 while let Some(&x) = it.next() {
580 assert_eq!(x, ys[i]);
582 assert_eq!(it.len(), 5-i);
584 assert_eq!(i, ys.len());
585 assert_eq!(it.len(), 0);
589 fn test_iterator_take_nth() {
590 let xs = [0, 1, 2, 4, 5];
591 let mut it = xs.iter();
593 let mut take = it.by_ref().take(3);
595 while let Some(&x) = take.nth(0) {
600 assert_eq!(it.nth(1), Some(&5));
601 assert_eq!(it.nth(0), None);
603 let xs = [0, 1, 2, 3, 4];
604 let mut it = xs.iter().take(7);
606 while let Some(&x) = it.nth(1) {
613 fn test_iterator_take_short() {
614 let xs = [0, 1, 2, 3];
615 let ys = [0, 1, 2, 3];
616 let mut it = xs.iter().take(5);
618 assert_eq!(it.len(), 4);
619 while let Some(&x) = it.next() {
620 assert_eq!(x, ys[i]);
622 assert_eq!(it.len(), 4-i);
624 assert_eq!(i, ys.len());
625 assert_eq!(it.len(), 0);
629 fn test_iterator_scan() {
630 // test the type inference
631 fn add(old: &mut isize, new: &usize) -> Option<f64> {
632 *old += *new as isize;
635 let xs = [0, 1, 2, 3, 4];
636 let ys = [0f64, 1.0, 3.0, 6.0, 10.0];
638 let it = xs.iter().scan(0, add);
641 assert_eq!(x, ys[i]);
644 assert_eq!(i, ys.len());
648 fn test_iterator_flat_map() {
650 let ys = [0, 1, 2, 3, 4, 5, 6, 7, 8];
651 let it = xs.iter().flat_map(|&x| (x..).step_by(1).take(3));
654 assert_eq!(x, ys[i]);
657 assert_eq!(i, ys.len());
662 let xs = [1, 2, 3, 4];
668 .collect::<Vec<usize>>();
670 assert_eq!(n, xs.len());
671 assert_eq!(&xs[..], &ys[..]);
677 let it = (0..).step_by(1).take(cycle_len).cycle();
678 assert_eq!(it.size_hint(), (usize::MAX, None));
679 for (i, x) in it.take(100).enumerate() {
680 assert_eq!(i % cycle_len, x);
683 let mut it = (0..).step_by(1).take(0).cycle();
684 assert_eq!(it.size_hint(), (0, Some(0)));
685 assert_eq!(it.next(), None);
689 fn test_iterator_nth() {
690 let v: &[_] = &[0, 1, 2, 3, 4];
691 for i in 0..v.len() {
692 assert_eq!(v.iter().nth(i).unwrap(), &v[i]);
694 assert_eq!(v.iter().nth(v.len()), None);
698 fn test_iterator_last() {
699 let v: &[_] = &[0, 1, 2, 3, 4];
700 assert_eq!(v.iter().last().unwrap(), &4);
701 assert_eq!(v[..1].iter().last().unwrap(), &0);
705 fn test_iterator_len() {
706 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
707 assert_eq!(v[..4].iter().count(), 4);
708 assert_eq!(v[..10].iter().count(), 10);
709 assert_eq!(v[..0].iter().count(), 0);
713 fn test_iterator_sum() {
714 let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
715 assert_eq!(v[..4].iter().cloned().sum::<i32>(), 6);
716 assert_eq!(v.iter().cloned().sum::<i32>(), 55);
717 assert_eq!(v[..0].iter().cloned().sum::<i32>(), 0);
721 fn test_iterator_sum_result() {
722 let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)];
723 assert_eq!(v.iter().cloned().sum::<Result<i32, _>>(), Ok(10));
724 let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)];
725 assert_eq!(v.iter().cloned().sum::<Result<i32, _>>(), Err(()));
729 fn test_iterator_product() {
730 let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
731 assert_eq!(v[..4].iter().cloned().product::<i32>(), 0);
732 assert_eq!(v[1..5].iter().cloned().product::<i32>(), 24);
733 assert_eq!(v[..0].iter().cloned().product::<i32>(), 1);
737 fn test_iterator_product_result() {
738 let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)];
739 assert_eq!(v.iter().cloned().product::<Result<i32, _>>(), Ok(24));
740 let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)];
741 assert_eq!(v.iter().cloned().product::<Result<i32, _>>(), Err(()));
745 fn test_iterator_max() {
746 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
747 assert_eq!(v[..4].iter().cloned().max(), Some(3));
748 assert_eq!(v.iter().cloned().max(), Some(10));
749 assert_eq!(v[..0].iter().cloned().max(), None);
753 fn test_iterator_min() {
754 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
755 assert_eq!(v[..4].iter().cloned().min(), Some(0));
756 assert_eq!(v.iter().cloned().min(), Some(0));
757 assert_eq!(v[..0].iter().cloned().min(), None);
761 fn test_iterator_size_hint() {
762 let c = (0..).step_by(1);
763 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
764 let v2 = &[10, 11, 12];
767 assert_eq!((0..).size_hint(), (usize::MAX, None));
768 assert_eq!(c.size_hint(), (usize::MAX, None));
769 assert_eq!(vi.clone().size_hint(), (10, Some(10)));
771 assert_eq!(c.clone().take(5).size_hint(), (5, Some(5)));
772 assert_eq!(c.clone().skip(5).size_hint().1, None);
773 assert_eq!(c.clone().take_while(|_| false).size_hint(), (0, None));
774 assert_eq!(c.clone().skip_while(|_| false).size_hint(), (0, None));
775 assert_eq!(c.clone().enumerate().size_hint(), (usize::MAX, None));
776 assert_eq!(c.clone().chain(vi.clone().cloned()).size_hint(), (usize::MAX, None));
777 assert_eq!(c.clone().zip(vi.clone()).size_hint(), (10, Some(10)));
778 assert_eq!(c.clone().scan(0, |_,_| Some(0)).size_hint(), (0, None));
779 assert_eq!(c.clone().filter(|_| false).size_hint(), (0, None));
780 assert_eq!(c.clone().map(|_| 0).size_hint(), (usize::MAX, None));
781 assert_eq!(c.filter_map(|_| Some(0)).size_hint(), (0, None));
783 assert_eq!(vi.clone().take(5).size_hint(), (5, Some(5)));
784 assert_eq!(vi.clone().take(12).size_hint(), (10, Some(10)));
785 assert_eq!(vi.clone().skip(3).size_hint(), (7, Some(7)));
786 assert_eq!(vi.clone().skip(12).size_hint(), (0, Some(0)));
787 assert_eq!(vi.clone().take_while(|_| false).size_hint(), (0, Some(10)));
788 assert_eq!(vi.clone().skip_while(|_| false).size_hint(), (0, Some(10)));
789 assert_eq!(vi.clone().enumerate().size_hint(), (10, Some(10)));
790 assert_eq!(vi.clone().chain(v2).size_hint(), (13, Some(13)));
791 assert_eq!(vi.clone().zip(v2).size_hint(), (3, Some(3)));
792 assert_eq!(vi.clone().scan(0, |_,_| Some(0)).size_hint(), (0, Some(10)));
793 assert_eq!(vi.clone().filter(|_| false).size_hint(), (0, Some(10)));
794 assert_eq!(vi.clone().map(|&i| i+1).size_hint(), (10, Some(10)));
795 assert_eq!(vi.filter_map(|_| Some(0)).size_hint(), (0, Some(10)));
800 let a = vec![1, 2, 3, 4, 5];
801 let b: Vec<isize> = a.iter().cloned().collect();
807 let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
808 assert!(v.iter().all(|&x| x < 10));
809 assert!(!v.iter().all(|&x| x % 2 == 0));
810 assert!(!v.iter().all(|&x| x > 100));
811 assert!(v[..0].iter().all(|_| panic!()));
816 let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
817 assert!(v.iter().any(|&x| x < 10));
818 assert!(v.iter().any(|&x| x % 2 == 0));
819 assert!(!v.iter().any(|&x| x > 100));
820 assert!(!v[..0].iter().any(|_| panic!()));
825 let v: &[isize] = &[1, 3, 9, 27, 103, 14, 11];
826 assert_eq!(*v.iter().find(|&&x| x & 1 == 0).unwrap(), 14);
827 assert_eq!(*v.iter().find(|&&x| x % 3 == 0).unwrap(), 3);
828 assert!(v.iter().find(|&&x| x % 12 == 0).is_none());
833 let v = &[1, 3, 9, 27, 103, 14, 11];
834 assert_eq!(v.iter().position(|x| *x & 1 == 0).unwrap(), 5);
835 assert_eq!(v.iter().position(|x| *x % 3 == 0).unwrap(), 1);
836 assert!(v.iter().position(|x| *x % 12 == 0).is_none());
841 let xs = &[1, 2, 2, 1, 5, 9, 0, 2];
842 assert_eq!(xs.iter().filter(|x| **x == 2).count(), 3);
843 assert_eq!(xs.iter().filter(|x| **x == 5).count(), 1);
844 assert_eq!(xs.iter().filter(|x| **x == 95).count(), 0);
848 fn test_max_by_key() {
849 let xs: &[isize] = &[-3, 0, 1, 5, -10];
850 assert_eq!(*xs.iter().max_by_key(|x| x.abs()).unwrap(), -10);
855 let xs: &[isize] = &[-3, 0, 1, 5, -10];
856 assert_eq!(*xs.iter().max_by(|x, y| x.abs().cmp(&y.abs())).unwrap(), -10);
860 fn test_min_by_key() {
861 let xs: &[isize] = &[-3, 0, 1, 5, -10];
862 assert_eq!(*xs.iter().min_by_key(|x| x.abs()).unwrap(), 0);
867 let xs: &[isize] = &[-3, 0, 1, 5, -10];
868 assert_eq!(*xs.iter().min_by(|x, y| x.abs().cmp(&y.abs())).unwrap(), 0);
874 // sum the first five values
875 let partial_sum = xs.by_ref().take(5).fold(0, |a, b| a + b);
876 assert_eq!(partial_sum, 10);
877 assert_eq!(xs.next(), Some(5));
882 let xs = [2, 4, 6, 8, 10, 12, 14, 16];
883 let mut it = xs.iter();
886 assert!(it.rev().cloned().collect::<Vec<isize>>() ==
887 vec![16, 14, 12, 10, 8, 6]);
892 let xs = [2, 4, 6, 8];
894 let mut it = xs.iter().cloned();
895 assert_eq!(it.len(), 4);
896 assert_eq!(it.next(), Some(2));
897 assert_eq!(it.len(), 3);
898 assert_eq!(it.next(), Some(4));
899 assert_eq!(it.len(), 2);
900 assert_eq!(it.next_back(), Some(8));
901 assert_eq!(it.len(), 1);
902 assert_eq!(it.next_back(), Some(6));
903 assert_eq!(it.len(), 0);
904 assert_eq!(it.next_back(), None);
908 fn test_double_ended_map() {
909 let xs = [1, 2, 3, 4, 5, 6];
910 let mut it = xs.iter().map(|&x| x * -1);
911 assert_eq!(it.next(), Some(-1));
912 assert_eq!(it.next(), Some(-2));
913 assert_eq!(it.next_back(), Some(-6));
914 assert_eq!(it.next_back(), Some(-5));
915 assert_eq!(it.next(), Some(-3));
916 assert_eq!(it.next_back(), Some(-4));
917 assert_eq!(it.next(), None);
921 fn test_double_ended_enumerate() {
922 let xs = [1, 2, 3, 4, 5, 6];
923 let mut it = xs.iter().cloned().enumerate();
924 assert_eq!(it.next(), Some((0, 1)));
925 assert_eq!(it.next(), Some((1, 2)));
926 assert_eq!(it.next_back(), Some((5, 6)));
927 assert_eq!(it.next_back(), Some((4, 5)));
928 assert_eq!(it.next_back(), Some((3, 4)));
929 assert_eq!(it.next_back(), Some((2, 3)));
930 assert_eq!(it.next(), None);
934 fn test_double_ended_zip() {
935 let xs = [1, 2, 3, 4, 5, 6];
936 let ys = [1, 2, 3, 7];
937 let a = xs.iter().cloned();
938 let b = ys.iter().cloned();
939 let mut it = a.zip(b);
940 assert_eq!(it.next(), Some((1, 1)));
941 assert_eq!(it.next(), Some((2, 2)));
942 assert_eq!(it.next_back(), Some((4, 7)));
943 assert_eq!(it.next_back(), Some((3, 3)));
944 assert_eq!(it.next(), None);
948 fn test_double_ended_filter() {
949 let xs = [1, 2, 3, 4, 5, 6];
950 let mut it = xs.iter().filter(|&x| *x & 1 == 0);
951 assert_eq!(it.next_back().unwrap(), &6);
952 assert_eq!(it.next_back().unwrap(), &4);
953 assert_eq!(it.next().unwrap(), &2);
954 assert_eq!(it.next_back(), None);
958 fn test_double_ended_filter_map() {
959 let xs = [1, 2, 3, 4, 5, 6];
960 let mut it = xs.iter().filter_map(|&x| if x & 1 == 0 { Some(x * 2) } else { None });
961 assert_eq!(it.next_back().unwrap(), 12);
962 assert_eq!(it.next_back().unwrap(), 8);
963 assert_eq!(it.next().unwrap(), 4);
964 assert_eq!(it.next_back(), None);
968 fn test_double_ended_chain() {
969 let xs = [1, 2, 3, 4, 5];
971 let mut it = xs.iter().chain(&ys).rev();
972 assert_eq!(it.next().unwrap(), &11);
973 assert_eq!(it.next().unwrap(), &9);
974 assert_eq!(it.next_back().unwrap(), &1);
975 assert_eq!(it.next_back().unwrap(), &2);
976 assert_eq!(it.next_back().unwrap(), &3);
977 assert_eq!(it.next_back().unwrap(), &4);
978 assert_eq!(it.next_back().unwrap(), &5);
979 assert_eq!(it.next_back().unwrap(), &7);
980 assert_eq!(it.next_back(), None);
983 // test that .chain() is well behaved with an unfused iterator
984 struct CrazyIterator(bool);
985 impl CrazyIterator { fn new() -> CrazyIterator { CrazyIterator(false) } }
986 impl Iterator for CrazyIterator {
988 fn next(&mut self) -> Option<i32> {
989 if self.0 { Some(99) } else { self.0 = true; None }
993 impl DoubleEndedIterator for CrazyIterator {
994 fn next_back(&mut self) -> Option<i32> {
999 assert_eq!(CrazyIterator::new().chain(0..10).rev().last(), Some(0));
1000 assert!((0..10).chain(CrazyIterator::new()).rev().any(|i| i == 0));
1004 fn test_rposition() {
1005 fn f(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'b' }
1006 fn g(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'd' }
1007 let v = [(0, 'a'), (1, 'b'), (2, 'c'), (3, 'b')];
1009 assert_eq!(v.iter().rposition(f), Some(3));
1010 assert!(v.iter().rposition(g).is_none());
1015 fn test_rposition_panic() {
1016 let v: [(Box<_>, Box<_>); 4] =
1017 [(box 0, box 0), (box 0, box 0),
1018 (box 0, box 0), (box 0, box 0)];
1020 v.iter().rposition(|_elt| {
1031 fn test_double_ended_flat_map() {
1034 let mut it = u.iter().flat_map(|x| &v[*x..v.len()]);
1035 assert_eq!(it.next_back().unwrap(), &8);
1036 assert_eq!(it.next().unwrap(), &5);
1037 assert_eq!(it.next_back().unwrap(), &7);
1038 assert_eq!(it.next_back().unwrap(), &6);
1039 assert_eq!(it.next_back().unwrap(), &8);
1040 assert_eq!(it.next().unwrap(), &6);
1041 assert_eq!(it.next_back().unwrap(), &7);
1042 assert_eq!(it.next_back(), None);
1043 assert_eq!(it.next(), None);
1044 assert_eq!(it.next_back(), None);
1048 fn test_double_ended_range() {
1049 assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]);
1050 for _ in (10..0).rev() {
1051 panic!("unreachable");
1054 assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]);
1055 for _ in (10..0).rev() {
1056 panic!("unreachable");
1062 assert_eq!((0..5).collect::<Vec<_>>(), [0, 1, 2, 3, 4]);
1063 assert_eq!((-10..-1).collect::<Vec<_>>(), [-10, -9, -8, -7, -6, -5, -4, -3, -2]);
1064 assert_eq!((0..5).rev().collect::<Vec<_>>(), [4, 3, 2, 1, 0]);
1065 assert_eq!((200..-5).count(), 0);
1066 assert_eq!((200..-5).rev().count(), 0);
1067 assert_eq!((200..200).count(), 0);
1068 assert_eq!((200..200).rev().count(), 0);
1070 assert_eq!((0..100).size_hint(), (100, Some(100)));
1071 // this test is only meaningful when sizeof usize < sizeof u64
1072 assert_eq!((usize::MAX - 1..usize::MAX).size_hint(), (1, Some(1)));
1073 assert_eq!((-10..-1).size_hint(), (9, Some(9)));
1074 assert_eq!((-1..-10).size_hint(), (0, Some(0)));
1076 assert_eq!((-70..58).size_hint(), (128, Some(128)));
1077 assert_eq!((-128..127).size_hint(), (255, Some(255)));
1078 assert_eq!((-2..isize::MAX).size_hint(),
1079 (isize::MAX as usize + 2, Some(isize::MAX as usize + 2)));
1083 fn test_range_step() {
1084 assert_eq!((0..20).step_by(5).collect::<Vec<isize>>(), [0, 5, 10, 15]);
1085 assert_eq!((20..0).step_by(-5).collect::<Vec<isize>>(), [20, 15, 10, 5]);
1086 assert_eq!((20..0).step_by(-6).collect::<Vec<isize>>(), [20, 14, 8, 2]);
1087 assert_eq!((200..255).step_by(50).collect::<Vec<u8>>(), [200, 250]);
1088 assert_eq!((200..-5).step_by(1).collect::<Vec<isize>>(), []);
1089 assert_eq!((200..200).step_by(1).collect::<Vec<isize>>(), []);
1091 assert_eq!((0..20).step_by(1).size_hint(), (20, Some(20)));
1092 assert_eq!((0..20).step_by(21).size_hint(), (1, Some(1)));
1093 assert_eq!((0..20).step_by(5).size_hint(), (4, Some(4)));
1094 assert_eq!((20..0).step_by(-5).size_hint(), (4, Some(4)));
1095 assert_eq!((20..0).step_by(-6).size_hint(), (4, Some(4)));
1096 assert_eq!((20..-5).step_by(1).size_hint(), (0, Some(0)));
1097 assert_eq!((20..20).step_by(1).size_hint(), (0, Some(0)));
1098 assert_eq!((0..1).step_by(0).size_hint(), (0, None));
1099 assert_eq!((i8::MAX..i8::MIN).step_by(i8::MIN).size_hint(), (2, Some(2)));
1100 assert_eq!((i16::MIN..i16::MAX).step_by(i16::MAX).size_hint(), (3, Some(3)));
1101 assert_eq!((isize::MIN..isize::MAX).step_by(1).size_hint(), (usize::MAX, Some(usize::MAX)));
1106 let mut it = repeat(42);
1107 assert_eq!(it.next(), Some(42));
1108 assert_eq!(it.next(), Some(42));
1109 assert_eq!(it.next(), Some(42));
1115 assert_eq!(it.len(), 3);
1116 assert_eq!(it.next(), Some(0));
1117 assert_eq!(it.len(), 2);
1118 assert_eq!(it.next(), Some(1));
1119 assert_eq!(it.len(), 1);
1120 assert_eq!(it.next(), Some(2));
1121 assert_eq!(it.len(), 0);
1122 assert_eq!(it.next(), None);
1123 assert_eq!(it.len(), 0);
1124 assert_eq!(it.next(), None);
1125 assert_eq!(it.len(), 0);
1126 assert_eq!(it.next(), None);
1127 assert_eq!(it.len(), 0);
1131 fn test_fuse_nth() {
1133 let mut it = xs.iter();
1135 assert_eq!(it.len(), 3);
1136 assert_eq!(it.nth(2), Some(&2));
1137 assert_eq!(it.len(), 0);
1138 assert_eq!(it.nth(2), None);
1139 assert_eq!(it.len(), 0);
1143 fn test_fuse_last() {
1147 assert_eq!(it.len(), 3);
1148 assert_eq!(it.last(), Some(&2));
1152 fn test_fuse_count() {
1156 assert_eq!(it.len(), 3);
1157 assert_eq!(it.count(), 3);
1158 // Can't check len now because count consumes.
1163 let mut it = once(42);
1164 assert_eq!(it.next(), Some(42));
1165 assert_eq!(it.next(), None);
1170 let mut it = empty::<i32>();
1171 assert_eq!(it.next(), None);
1175 fn test_chain_fold() {
1179 let mut iter = xs.iter().chain(&ys);
1181 let mut result = Vec::new();
1182 iter.fold((), |(), &elt| result.push(elt));
1183 assert_eq!(&[2, 3, 1, 2, 0], &result[..]);
1187 fn test_step_replace_unsigned() {
1189 let y = x.replace_zero();
1194 let y = x.replace_one();
1200 fn test_step_replace_signed() {
1202 let y = x.replace_zero();
1207 let y = x.replace_one();
1213 fn test_step_replace_no_between() {
1215 let y = x.replace_zero();
1220 let y = x.replace_one();