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};
15 // FIXME #27741: This is here to simplify calling Iterator::step_by. Remove
16 // once Range::step_by is completely gone (not just deprecated).
18 fn iter_step_by(self, n: usize) -> StepBy<Self>;
20 impl<I:Iterator> IterEx for I {
21 fn iter_step_by(self, n: usize) -> StepBy<Self> { self.step_by(n) }
26 let empty: [isize; 0] = [];
30 assert!(!xs.iter().lt(ys.iter()));
31 assert!(!xs.iter().le(ys.iter()));
32 assert!( xs.iter().gt(ys.iter()));
33 assert!( xs.iter().ge(ys.iter()));
35 assert!( ys.iter().lt(xs.iter()));
36 assert!( ys.iter().le(xs.iter()));
37 assert!(!ys.iter().gt(xs.iter()));
38 assert!(!ys.iter().ge(xs.iter()));
40 assert!( empty.iter().lt(xs.iter()));
41 assert!( empty.iter().le(xs.iter()));
42 assert!(!empty.iter().gt(xs.iter()));
43 assert!(!empty.iter().ge(xs.iter()));
46 let u = [1.0f64, 2.0];
47 let v = [0.0f64/0.0, 3.0];
49 assert!(!u.iter().lt(v.iter()));
50 assert!(!u.iter().le(v.iter()));
51 assert!(!u.iter().gt(v.iter()));
52 assert!(!u.iter().ge(v.iter()));
58 assert!(a.iter().lt(b.iter()) == (a[0] < b[0]));
59 assert!(a.iter().le(b.iter()) == (a[0] <= b[0]));
60 assert!(a.iter().gt(b.iter()) == (a[0] > b[0]));
61 assert!(a.iter().ge(b.iter()) == (a[0] >= b[0]));
63 assert!(c.iter().lt(b.iter()) == (c[0] < b[0]));
64 assert!(c.iter().le(b.iter()) == (c[0] <= b[0]));
65 assert!(c.iter().gt(b.iter()) == (c[0] > b[0]));
66 assert!(c.iter().ge(b.iter()) == (c[0] >= b[0]));
70 fn test_multi_iter() {
73 assert!(xs.iter().eq(ys.iter().rev()));
74 assert!(xs.iter().lt(xs.iter().skip(2)));
78 fn test_counter_from_iter() {
79 let it = (0..).iter_step_by(5).take(10);
80 let xs: Vec<isize> = FromIterator::from_iter(it);
81 assert_eq!(xs, [0, 5, 10, 15, 20, 25, 30, 35, 40, 45]);
85 fn test_iterator_chain() {
86 let xs = [0, 1, 2, 3, 4, 5];
87 let ys = [30, 40, 50, 60];
88 let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
89 let it = xs.iter().chain(&ys);
92 assert_eq!(x, expected[i]);
95 assert_eq!(i, expected.len());
97 let ys = (30..).iter_step_by(10).take(4);
98 let it = xs.iter().cloned().chain(ys);
101 assert_eq!(x, expected[i]);
104 assert_eq!(i, expected.len());
108 fn test_iterator_chain_nth() {
109 let xs = [0, 1, 2, 3, 4, 5];
110 let ys = [30, 40, 50, 60];
112 let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
113 for (i, x) in expected.iter().enumerate() {
114 assert_eq!(Some(x), xs.iter().chain(&ys).nth(i));
116 assert_eq!(zs.iter().chain(&xs).nth(0), Some(&0));
118 let mut it = xs.iter().chain(&zs);
119 assert_eq!(it.nth(5), Some(&5));
120 assert_eq!(it.next(), None);
124 fn test_iterator_chain_last() {
125 let xs = [0, 1, 2, 3, 4, 5];
126 let ys = [30, 40, 50, 60];
128 assert_eq!(xs.iter().chain(&ys).last(), Some(&60));
129 assert_eq!(zs.iter().chain(&ys).last(), Some(&60));
130 assert_eq!(ys.iter().chain(&zs).last(), Some(&60));
131 assert_eq!(zs.iter().chain(&zs).last(), None);
135 fn test_iterator_chain_count() {
136 let xs = [0, 1, 2, 3, 4, 5];
137 let ys = [30, 40, 50, 60];
139 assert_eq!(xs.iter().chain(&ys).count(), 10);
140 assert_eq!(zs.iter().chain(&ys).count(), 4);
144 fn test_iterator_chain_find() {
145 let xs = [0, 1, 2, 3, 4, 5];
146 let ys = [30, 40, 50, 60];
147 let mut iter = xs.iter().chain(&ys);
148 assert_eq!(iter.find(|&&i| i == 4), Some(&4));
149 assert_eq!(iter.next(), Some(&5));
150 assert_eq!(iter.find(|&&i| i == 40), Some(&40));
151 assert_eq!(iter.next(), Some(&50));
152 assert_eq!(iter.find(|&&i| i == 100), None);
153 assert_eq!(iter.next(), None);
157 fn test_iterator_step_by() {
159 let mut it = (0..).iter_step_by(1).take(3);
160 assert_eq!(it.next(), Some(0));
161 assert_eq!(it.next(), Some(1));
162 assert_eq!(it.next(), Some(2));
163 assert_eq!(it.next(), None);
165 let mut it = (0..).iter_step_by(3).take(4);
166 assert_eq!(it.next(), Some(0));
167 assert_eq!(it.next(), Some(3));
168 assert_eq!(it.next(), Some(6));
169 assert_eq!(it.next(), Some(9));
170 assert_eq!(it.next(), None);
175 fn test_iterator_step_by_zero() {
176 let mut it = (0..).iter_step_by(0);
181 fn test_iterator_step_by_size_hint() {
182 struct StubSizeHint(usize, Option<usize>);
183 impl Iterator for StubSizeHint {
185 fn next(&mut self) -> Option<()> {
187 if let Some(ref mut upper) = self.1 {
192 fn size_hint(&self) -> (usize, Option<usize>) {
197 // The two checks in each case are needed because the logic
198 // is different before the first call to `next()`.
200 let mut it = StubSizeHint(10, Some(10)).step_by(1);
201 assert_eq!(it.size_hint(), (10, Some(10)));
203 assert_eq!(it.size_hint(), (9, Some(9)));
206 let mut it = StubSizeHint(10, Some(10)).step_by(3);
207 assert_eq!(it.size_hint(), (4, Some(4)));
209 assert_eq!(it.size_hint(), (3, Some(3)));
211 // larger base range, but not enough to get another element
212 let mut it = StubSizeHint(12, Some(12)).step_by(3);
213 assert_eq!(it.size_hint(), (4, Some(4)));
215 assert_eq!(it.size_hint(), (3, Some(3)));
217 // smaller base range, so fewer resulting elements
218 let mut it = StubSizeHint(9, Some(9)).step_by(3);
219 assert_eq!(it.size_hint(), (3, Some(3)));
221 assert_eq!(it.size_hint(), (2, Some(2)));
223 // infinite upper bound
224 let mut it = StubSizeHint(usize::MAX, None).step_by(1);
225 assert_eq!(it.size_hint(), (usize::MAX, None));
227 assert_eq!(it.size_hint(), (usize::MAX-1, None));
229 // still infinite with larger step
230 let mut it = StubSizeHint(7, None).step_by(3);
231 assert_eq!(it.size_hint(), (3, None));
233 assert_eq!(it.size_hint(), (2, None));
235 // propagates ExactSizeIterator
237 let it = a.iter().step_by(2);
238 assert_eq!(it.len(), 3);
240 // Cannot be TrustedLen as a step greater than one makes an iterator
241 // with (usize::MAX, None) no longer meet the safety requirements
242 trait TrustedLenCheck { fn test(self) -> bool; }
243 impl<T:Iterator> TrustedLenCheck for T {
244 default fn test(self) -> bool { false }
246 impl<T:TrustedLen> TrustedLenCheck for T {
247 fn test(self) -> bool { true }
249 assert!(TrustedLenCheck::test(a.iter()));
250 assert!(!TrustedLenCheck::test(a.iter().step_by(1)));
254 fn test_filter_map() {
255 let it = (0..).iter_step_by(1).take(10)
256 .filter_map(|x| if x % 2 == 0 { Some(x*x) } else { None });
257 assert_eq!(it.collect::<Vec<usize>>(), [0*0, 2*2, 4*4, 6*6, 8*8]);
261 fn test_iterator_enumerate() {
262 let xs = [0, 1, 2, 3, 4, 5];
263 let it = xs.iter().enumerate();
270 fn test_iterator_enumerate_nth() {
271 let xs = [0, 1, 2, 3, 4, 5];
272 for (i, &x) in xs.iter().enumerate() {
276 let mut it = xs.iter().enumerate();
277 while let Some((i, &x)) = it.nth(0) {
281 let mut it = xs.iter().enumerate();
282 while let Some((i, &x)) = it.nth(1) {
286 let (i, &x) = xs.iter().enumerate().nth(3).unwrap();
292 fn test_iterator_enumerate_count() {
293 let xs = [0, 1, 2, 3, 4, 5];
294 assert_eq!(xs.iter().count(), 6);
298 fn test_iterator_filter_count() {
299 let xs = [0, 1, 2, 3, 4, 5, 6, 7, 8];
300 assert_eq!(xs.iter().filter(|&&x| x % 2 == 0).count(), 5);
304 fn test_iterator_peekable() {
305 let xs = vec![0, 1, 2, 3, 4, 5];
306 let mut it = xs.iter().cloned().peekable();
308 assert_eq!(it.len(), 6);
309 assert_eq!(it.peek().unwrap(), &0);
310 assert_eq!(it.len(), 6);
311 assert_eq!(it.next().unwrap(), 0);
312 assert_eq!(it.len(), 5);
313 assert_eq!(it.next().unwrap(), 1);
314 assert_eq!(it.len(), 4);
315 assert_eq!(it.next().unwrap(), 2);
316 assert_eq!(it.len(), 3);
317 assert_eq!(it.peek().unwrap(), &3);
318 assert_eq!(it.len(), 3);
319 assert_eq!(it.peek().unwrap(), &3);
320 assert_eq!(it.len(), 3);
321 assert_eq!(it.next().unwrap(), 3);
322 assert_eq!(it.len(), 2);
323 assert_eq!(it.next().unwrap(), 4);
324 assert_eq!(it.len(), 1);
325 assert_eq!(it.peek().unwrap(), &5);
326 assert_eq!(it.len(), 1);
327 assert_eq!(it.next().unwrap(), 5);
328 assert_eq!(it.len(), 0);
329 assert!(it.peek().is_none());
330 assert_eq!(it.len(), 0);
331 assert!(it.next().is_none());
332 assert_eq!(it.len(), 0);
336 fn test_iterator_peekable_count() {
337 let xs = [0, 1, 2, 3, 4, 5];
339 let zs: [i32; 0] = [];
341 assert_eq!(xs.iter().peekable().count(), 6);
343 let mut it = xs.iter().peekable();
344 assert_eq!(it.peek(), Some(&&0));
345 assert_eq!(it.count(), 6);
347 assert_eq!(ys.iter().peekable().count(), 1);
349 let mut it = ys.iter().peekable();
350 assert_eq!(it.peek(), Some(&&10));
351 assert_eq!(it.count(), 1);
353 assert_eq!(zs.iter().peekable().count(), 0);
355 let mut it = zs.iter().peekable();
356 assert_eq!(it.peek(), None);
361 fn test_iterator_peekable_nth() {
362 let xs = [0, 1, 2, 3, 4, 5];
363 let mut it = xs.iter().peekable();
365 assert_eq!(it.peek(), Some(&&0));
366 assert_eq!(it.nth(0), Some(&0));
367 assert_eq!(it.peek(), Some(&&1));
368 assert_eq!(it.nth(1), Some(&2));
369 assert_eq!(it.peek(), Some(&&3));
370 assert_eq!(it.nth(2), Some(&5));
371 assert_eq!(it.next(), None);
375 fn test_iterator_peekable_last() {
376 let xs = [0, 1, 2, 3, 4, 5];
379 let mut it = xs.iter().peekable();
380 assert_eq!(it.peek(), Some(&&0));
381 assert_eq!(it.last(), Some(&5));
383 let mut it = ys.iter().peekable();
384 assert_eq!(it.peek(), Some(&&0));
385 assert_eq!(it.last(), Some(&0));
387 let mut it = ys.iter().peekable();
388 assert_eq!(it.next(), Some(&0));
389 assert_eq!(it.peek(), None);
390 assert_eq!(it.last(), None);
393 /// This is an iterator that follows the Iterator contract,
394 /// but it is not fused. After having returned None once, it will start
395 /// producing elements if .next() is called again.
396 pub struct CycleIter<'a, T: 'a> {
401 pub fn cycle<T>(data: &[T]) -> CycleIter<T> {
408 impl<'a, T> Iterator for CycleIter<'a, T> {
410 fn next(&mut self) -> Option<Self::Item> {
411 let elt = self.data.get(self.index);
413 self.index %= 1 + self.data.len();
419 fn test_iterator_peekable_remember_peek_none_1() {
420 // Check that the loop using .peek() terminates
421 let data = [1, 2, 3];
422 let mut iter = cycle(&data).peekable();
425 while let Some(_) = iter.next() {
426 let is_the_last = iter.peek().is_none();
427 assert_eq!(is_the_last, n == data.len() - 1);
429 if n > data.len() { break; }
431 assert_eq!(n, data.len());
435 fn test_iterator_peekable_remember_peek_none_2() {
437 let mut iter = cycle(&data).peekable();
439 assert_eq!(iter.peek(), None);
440 assert_eq!(iter.last(), None);
444 fn test_iterator_peekable_remember_peek_none_3() {
446 let mut iter = cycle(&data).peekable();
448 assert_eq!(iter.nth(0), Some(&0));
450 let mut iter = cycle(&data).peekable();
452 assert_eq!(iter.peek(), None);
453 assert_eq!(iter.nth(0), None);
457 fn test_iterator_take_while() {
458 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
459 let ys = [0, 1, 2, 3, 5, 13];
460 let it = xs.iter().take_while(|&x| *x < 15);
463 assert_eq!(*x, ys[i]);
466 assert_eq!(i, ys.len());
470 fn test_iterator_skip_while() {
471 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
472 let ys = [15, 16, 17, 19];
473 let it = xs.iter().skip_while(|&x| *x < 15);
476 assert_eq!(*x, ys[i]);
479 assert_eq!(i, ys.len());
483 fn test_iterator_skip() {
484 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
485 let ys = [13, 15, 16, 17, 19, 20, 30];
486 let mut it = xs.iter().skip(5);
488 while let Some(&x) = it.next() {
489 assert_eq!(x, ys[i]);
491 assert_eq!(it.len(), xs.len()-5-i);
493 assert_eq!(i, ys.len());
494 assert_eq!(it.len(), 0);
498 fn test_iterator_skip_doubleended() {
499 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
500 let mut it = xs.iter().rev().skip(5);
501 assert_eq!(it.next(), Some(&15));
502 assert_eq!(it.by_ref().rev().next(), Some(&0));
503 assert_eq!(it.next(), Some(&13));
504 assert_eq!(it.by_ref().rev().next(), Some(&1));
505 assert_eq!(it.next(), Some(&5));
506 assert_eq!(it.by_ref().rev().next(), Some(&2));
507 assert_eq!(it.next(), Some(&3));
508 assert_eq!(it.next(), None);
509 let mut it = xs.iter().rev().skip(5).rev();
510 assert_eq!(it.next(), Some(&0));
511 assert_eq!(it.rev().next(), Some(&15));
512 let mut it_base = xs.iter();
514 let mut it = it_base.by_ref().skip(5).rev();
515 assert_eq!(it.next(), Some(&30));
516 assert_eq!(it.next(), Some(&20));
517 assert_eq!(it.next(), Some(&19));
518 assert_eq!(it.next(), Some(&17));
519 assert_eq!(it.next(), Some(&16));
520 assert_eq!(it.next(), Some(&15));
521 assert_eq!(it.next(), Some(&13));
522 assert_eq!(it.next(), None);
524 // make sure the skipped parts have not been consumed
525 assert_eq!(it_base.next(), Some(&0));
526 assert_eq!(it_base.next(), Some(&1));
527 assert_eq!(it_base.next(), Some(&2));
528 assert_eq!(it_base.next(), Some(&3));
529 assert_eq!(it_base.next(), Some(&5));
530 assert_eq!(it_base.next(), None);
531 let it = xs.iter().skip(5).rev();
532 assert_eq!(it.last(), Some(&13));
536 fn test_iterator_skip_nth() {
537 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
539 let mut it = xs.iter().skip(0);
540 assert_eq!(it.nth(0), Some(&0));
541 assert_eq!(it.nth(1), Some(&2));
543 let mut it = xs.iter().skip(5);
544 assert_eq!(it.nth(0), Some(&13));
545 assert_eq!(it.nth(1), Some(&16));
547 let mut it = xs.iter().skip(12);
548 assert_eq!(it.nth(0), None);
553 fn test_iterator_skip_count() {
554 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
556 assert_eq!(xs.iter().skip(0).count(), 12);
557 assert_eq!(xs.iter().skip(1).count(), 11);
558 assert_eq!(xs.iter().skip(11).count(), 1);
559 assert_eq!(xs.iter().skip(12).count(), 0);
560 assert_eq!(xs.iter().skip(13).count(), 0);
564 fn test_iterator_skip_last() {
565 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
567 assert_eq!(xs.iter().skip(0).last(), Some(&30));
568 assert_eq!(xs.iter().skip(1).last(), Some(&30));
569 assert_eq!(xs.iter().skip(11).last(), Some(&30));
570 assert_eq!(xs.iter().skip(12).last(), None);
571 assert_eq!(xs.iter().skip(13).last(), None);
573 let mut it = xs.iter().skip(5);
574 assert_eq!(it.next(), Some(&13));
575 assert_eq!(it.last(), Some(&30));
579 fn test_iterator_take() {
580 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
581 let ys = [0, 1, 2, 3, 5];
582 let mut it = xs.iter().take(5);
584 assert_eq!(it.len(), 5);
585 while let Some(&x) = it.next() {
586 assert_eq!(x, ys[i]);
588 assert_eq!(it.len(), 5-i);
590 assert_eq!(i, ys.len());
591 assert_eq!(it.len(), 0);
595 fn test_iterator_take_nth() {
596 let xs = [0, 1, 2, 4, 5];
597 let mut it = xs.iter();
599 let mut take = it.by_ref().take(3);
601 while let Some(&x) = take.nth(0) {
606 assert_eq!(it.nth(1), Some(&5));
607 assert_eq!(it.nth(0), None);
609 let xs = [0, 1, 2, 3, 4];
610 let mut it = xs.iter().take(7);
612 while let Some(&x) = it.nth(1) {
619 fn test_iterator_take_short() {
620 let xs = [0, 1, 2, 3];
621 let ys = [0, 1, 2, 3];
622 let mut it = xs.iter().take(5);
624 assert_eq!(it.len(), 4);
625 while let Some(&x) = it.next() {
626 assert_eq!(x, ys[i]);
628 assert_eq!(it.len(), 4-i);
630 assert_eq!(i, ys.len());
631 assert_eq!(it.len(), 0);
635 fn test_iterator_scan() {
636 // test the type inference
637 fn add(old: &mut isize, new: &usize) -> Option<f64> {
638 *old += *new as isize;
641 let xs = [0, 1, 2, 3, 4];
642 let ys = [0f64, 1.0, 3.0, 6.0, 10.0];
644 let it = xs.iter().scan(0, add);
647 assert_eq!(x, ys[i]);
650 assert_eq!(i, ys.len());
654 fn test_iterator_flat_map() {
656 let ys = [0, 1, 2, 3, 4, 5, 6, 7, 8];
657 let it = xs.iter().flat_map(|&x| (x..).iter_step_by(1).take(3));
660 assert_eq!(x, ys[i]);
663 assert_eq!(i, ys.len());
668 let xs = [1, 2, 3, 4];
674 .collect::<Vec<usize>>();
676 assert_eq!(n, xs.len());
677 assert_eq!(&xs[..], &ys[..]);
683 let it = (0..).iter_step_by(1).take(cycle_len).cycle();
684 assert_eq!(it.size_hint(), (usize::MAX, None));
685 for (i, x) in it.take(100).enumerate() {
686 assert_eq!(i % cycle_len, x);
689 let mut it = (0..).iter_step_by(1).take(0).cycle();
690 assert_eq!(it.size_hint(), (0, Some(0)));
691 assert_eq!(it.next(), None);
695 fn test_iterator_nth() {
696 let v: &[_] = &[0, 1, 2, 3, 4];
697 for i in 0..v.len() {
698 assert_eq!(v.iter().nth(i).unwrap(), &v[i]);
700 assert_eq!(v.iter().nth(v.len()), None);
704 fn test_iterator_last() {
705 let v: &[_] = &[0, 1, 2, 3, 4];
706 assert_eq!(v.iter().last().unwrap(), &4);
707 assert_eq!(v[..1].iter().last().unwrap(), &0);
711 fn test_iterator_len() {
712 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
713 assert_eq!(v[..4].iter().count(), 4);
714 assert_eq!(v[..10].iter().count(), 10);
715 assert_eq!(v[..0].iter().count(), 0);
719 fn test_iterator_sum() {
720 let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
721 assert_eq!(v[..4].iter().cloned().sum::<i32>(), 6);
722 assert_eq!(v.iter().cloned().sum::<i32>(), 55);
723 assert_eq!(v[..0].iter().cloned().sum::<i32>(), 0);
727 fn test_iterator_sum_result() {
728 let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)];
729 assert_eq!(v.iter().cloned().sum::<Result<i32, _>>(), Ok(10));
730 let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)];
731 assert_eq!(v.iter().cloned().sum::<Result<i32, _>>(), Err(()));
735 fn test_iterator_product() {
736 let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
737 assert_eq!(v[..4].iter().cloned().product::<i32>(), 0);
738 assert_eq!(v[1..5].iter().cloned().product::<i32>(), 24);
739 assert_eq!(v[..0].iter().cloned().product::<i32>(), 1);
743 fn test_iterator_product_result() {
744 let v: &[Result<i32, ()>] = &[Ok(1), Ok(2), Ok(3), Ok(4)];
745 assert_eq!(v.iter().cloned().product::<Result<i32, _>>(), Ok(24));
746 let v: &[Result<i32, ()>] = &[Ok(1), Err(()), Ok(3), Ok(4)];
747 assert_eq!(v.iter().cloned().product::<Result<i32, _>>(), Err(()));
751 fn test_iterator_max() {
752 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
753 assert_eq!(v[..4].iter().cloned().max(), Some(3));
754 assert_eq!(v.iter().cloned().max(), Some(10));
755 assert_eq!(v[..0].iter().cloned().max(), None);
759 fn test_iterator_min() {
760 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
761 assert_eq!(v[..4].iter().cloned().min(), Some(0));
762 assert_eq!(v.iter().cloned().min(), Some(0));
763 assert_eq!(v[..0].iter().cloned().min(), None);
767 fn test_iterator_size_hint() {
768 let c = (0..).iter_step_by(1);
769 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
770 let v2 = &[10, 11, 12];
773 assert_eq!((0..).size_hint(), (usize::MAX, None));
774 assert_eq!(c.size_hint(), (usize::MAX, None));
775 assert_eq!(vi.clone().size_hint(), (10, Some(10)));
777 assert_eq!(c.clone().take(5).size_hint(), (5, Some(5)));
778 assert_eq!(c.clone().skip(5).size_hint().1, None);
779 assert_eq!(c.clone().take_while(|_| false).size_hint(), (0, None));
780 assert_eq!(c.clone().skip_while(|_| false).size_hint(), (0, None));
781 assert_eq!(c.clone().enumerate().size_hint(), (usize::MAX, None));
782 assert_eq!(c.clone().chain(vi.clone().cloned()).size_hint(), (usize::MAX, None));
783 assert_eq!(c.clone().zip(vi.clone()).size_hint(), (10, Some(10)));
784 assert_eq!(c.clone().scan(0, |_,_| Some(0)).size_hint(), (0, None));
785 assert_eq!(c.clone().filter(|_| false).size_hint(), (0, None));
786 assert_eq!(c.clone().map(|_| 0).size_hint(), (usize::MAX, None));
787 assert_eq!(c.filter_map(|_| Some(0)).size_hint(), (0, None));
789 assert_eq!(vi.clone().take(5).size_hint(), (5, Some(5)));
790 assert_eq!(vi.clone().take(12).size_hint(), (10, Some(10)));
791 assert_eq!(vi.clone().skip(3).size_hint(), (7, Some(7)));
792 assert_eq!(vi.clone().skip(12).size_hint(), (0, Some(0)));
793 assert_eq!(vi.clone().take_while(|_| false).size_hint(), (0, Some(10)));
794 assert_eq!(vi.clone().skip_while(|_| false).size_hint(), (0, Some(10)));
795 assert_eq!(vi.clone().enumerate().size_hint(), (10, Some(10)));
796 assert_eq!(vi.clone().chain(v2).size_hint(), (13, Some(13)));
797 assert_eq!(vi.clone().zip(v2).size_hint(), (3, Some(3)));
798 assert_eq!(vi.clone().scan(0, |_,_| Some(0)).size_hint(), (0, Some(10)));
799 assert_eq!(vi.clone().filter(|_| false).size_hint(), (0, Some(10)));
800 assert_eq!(vi.clone().map(|&i| i+1).size_hint(), (10, Some(10)));
801 assert_eq!(vi.filter_map(|_| Some(0)).size_hint(), (0, Some(10)));
806 let a = vec![1, 2, 3, 4, 5];
807 let b: Vec<isize> = a.iter().cloned().collect();
813 let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
814 assert!(v.iter().all(|&x| x < 10));
815 assert!(!v.iter().all(|&x| x % 2 == 0));
816 assert!(!v.iter().all(|&x| x > 100));
817 assert!(v[..0].iter().all(|_| panic!()));
822 let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
823 assert!(v.iter().any(|&x| x < 10));
824 assert!(v.iter().any(|&x| x % 2 == 0));
825 assert!(!v.iter().any(|&x| x > 100));
826 assert!(!v[..0].iter().any(|_| panic!()));
831 let v: &[isize] = &[1, 3, 9, 27, 103, 14, 11];
832 assert_eq!(*v.iter().find(|&&x| x & 1 == 0).unwrap(), 14);
833 assert_eq!(*v.iter().find(|&&x| x % 3 == 0).unwrap(), 3);
834 assert!(v.iter().find(|&&x| x % 12 == 0).is_none());
839 let v = &[1, 3, 9, 27, 103, 14, 11];
840 assert_eq!(v.iter().position(|x| *x & 1 == 0).unwrap(), 5);
841 assert_eq!(v.iter().position(|x| *x % 3 == 0).unwrap(), 1);
842 assert!(v.iter().position(|x| *x % 12 == 0).is_none());
847 let xs = &[1, 2, 2, 1, 5, 9, 0, 2];
848 assert_eq!(xs.iter().filter(|x| **x == 2).count(), 3);
849 assert_eq!(xs.iter().filter(|x| **x == 5).count(), 1);
850 assert_eq!(xs.iter().filter(|x| **x == 95).count(), 0);
854 fn test_max_by_key() {
855 let xs: &[isize] = &[-3, 0, 1, 5, -10];
856 assert_eq!(*xs.iter().max_by_key(|x| x.abs()).unwrap(), -10);
861 let xs: &[isize] = &[-3, 0, 1, 5, -10];
862 assert_eq!(*xs.iter().max_by(|x, y| x.abs().cmp(&y.abs())).unwrap(), -10);
866 fn test_min_by_key() {
867 let xs: &[isize] = &[-3, 0, 1, 5, -10];
868 assert_eq!(*xs.iter().min_by_key(|x| x.abs()).unwrap(), 0);
873 let xs: &[isize] = &[-3, 0, 1, 5, -10];
874 assert_eq!(*xs.iter().min_by(|x, y| x.abs().cmp(&y.abs())).unwrap(), 0);
880 // sum the first five values
881 let partial_sum = xs.by_ref().take(5).fold(0, |a, b| a + b);
882 assert_eq!(partial_sum, 10);
883 assert_eq!(xs.next(), Some(5));
888 let xs = [2, 4, 6, 8, 10, 12, 14, 16];
889 let mut it = xs.iter();
892 assert!(it.rev().cloned().collect::<Vec<isize>>() ==
893 vec![16, 14, 12, 10, 8, 6]);
898 let xs = [2, 4, 6, 8];
900 let mut it = xs.iter().cloned();
901 assert_eq!(it.len(), 4);
902 assert_eq!(it.next(), Some(2));
903 assert_eq!(it.len(), 3);
904 assert_eq!(it.next(), Some(4));
905 assert_eq!(it.len(), 2);
906 assert_eq!(it.next_back(), Some(8));
907 assert_eq!(it.len(), 1);
908 assert_eq!(it.next_back(), Some(6));
909 assert_eq!(it.len(), 0);
910 assert_eq!(it.next_back(), None);
914 fn test_double_ended_map() {
915 let xs = [1, 2, 3, 4, 5, 6];
916 let mut it = xs.iter().map(|&x| x * -1);
917 assert_eq!(it.next(), Some(-1));
918 assert_eq!(it.next(), Some(-2));
919 assert_eq!(it.next_back(), Some(-6));
920 assert_eq!(it.next_back(), Some(-5));
921 assert_eq!(it.next(), Some(-3));
922 assert_eq!(it.next_back(), Some(-4));
923 assert_eq!(it.next(), None);
927 fn test_double_ended_enumerate() {
928 let xs = [1, 2, 3, 4, 5, 6];
929 let mut it = xs.iter().cloned().enumerate();
930 assert_eq!(it.next(), Some((0, 1)));
931 assert_eq!(it.next(), Some((1, 2)));
932 assert_eq!(it.next_back(), Some((5, 6)));
933 assert_eq!(it.next_back(), Some((4, 5)));
934 assert_eq!(it.next_back(), Some((3, 4)));
935 assert_eq!(it.next_back(), Some((2, 3)));
936 assert_eq!(it.next(), None);
940 fn test_double_ended_zip() {
941 let xs = [1, 2, 3, 4, 5, 6];
942 let ys = [1, 2, 3, 7];
943 let a = xs.iter().cloned();
944 let b = ys.iter().cloned();
945 let mut it = a.zip(b);
946 assert_eq!(it.next(), Some((1, 1)));
947 assert_eq!(it.next(), Some((2, 2)));
948 assert_eq!(it.next_back(), Some((4, 7)));
949 assert_eq!(it.next_back(), Some((3, 3)));
950 assert_eq!(it.next(), None);
954 fn test_double_ended_filter() {
955 let xs = [1, 2, 3, 4, 5, 6];
956 let mut it = xs.iter().filter(|&x| *x & 1 == 0);
957 assert_eq!(it.next_back().unwrap(), &6);
958 assert_eq!(it.next_back().unwrap(), &4);
959 assert_eq!(it.next().unwrap(), &2);
960 assert_eq!(it.next_back(), None);
964 fn test_double_ended_filter_map() {
965 let xs = [1, 2, 3, 4, 5, 6];
966 let mut it = xs.iter().filter_map(|&x| if x & 1 == 0 { Some(x * 2) } else { None });
967 assert_eq!(it.next_back().unwrap(), 12);
968 assert_eq!(it.next_back().unwrap(), 8);
969 assert_eq!(it.next().unwrap(), 4);
970 assert_eq!(it.next_back(), None);
974 fn test_double_ended_chain() {
975 let xs = [1, 2, 3, 4, 5];
977 let mut it = xs.iter().chain(&ys).rev();
978 assert_eq!(it.next().unwrap(), &11);
979 assert_eq!(it.next().unwrap(), &9);
980 assert_eq!(it.next_back().unwrap(), &1);
981 assert_eq!(it.next_back().unwrap(), &2);
982 assert_eq!(it.next_back().unwrap(), &3);
983 assert_eq!(it.next_back().unwrap(), &4);
984 assert_eq!(it.next_back().unwrap(), &5);
985 assert_eq!(it.next_back().unwrap(), &7);
986 assert_eq!(it.next_back(), None);
989 // test that .chain() is well behaved with an unfused iterator
990 struct CrazyIterator(bool);
991 impl CrazyIterator { fn new() -> CrazyIterator { CrazyIterator(false) } }
992 impl Iterator for CrazyIterator {
994 fn next(&mut self) -> Option<i32> {
995 if self.0 { Some(99) } else { self.0 = true; None }
999 impl DoubleEndedIterator for CrazyIterator {
1000 fn next_back(&mut self) -> Option<i32> {
1005 assert_eq!(CrazyIterator::new().chain(0..10).rev().last(), Some(0));
1006 assert!((0..10).chain(CrazyIterator::new()).rev().any(|i| i == 0));
1010 fn test_rposition() {
1011 fn f(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'b' }
1012 fn g(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'd' }
1013 let v = [(0, 'a'), (1, 'b'), (2, 'c'), (3, 'b')];
1015 assert_eq!(v.iter().rposition(f), Some(3));
1016 assert!(v.iter().rposition(g).is_none());
1021 fn test_rposition_panic() {
1022 let v: [(Box<_>, Box<_>); 4] =
1023 [(box 0, box 0), (box 0, box 0),
1024 (box 0, box 0), (box 0, box 0)];
1026 v.iter().rposition(|_elt| {
1037 fn test_double_ended_flat_map() {
1040 let mut it = u.iter().flat_map(|x| &v[*x..v.len()]);
1041 assert_eq!(it.next_back().unwrap(), &8);
1042 assert_eq!(it.next().unwrap(), &5);
1043 assert_eq!(it.next_back().unwrap(), &7);
1044 assert_eq!(it.next_back().unwrap(), &6);
1045 assert_eq!(it.next_back().unwrap(), &8);
1046 assert_eq!(it.next().unwrap(), &6);
1047 assert_eq!(it.next_back().unwrap(), &7);
1048 assert_eq!(it.next_back(), None);
1049 assert_eq!(it.next(), None);
1050 assert_eq!(it.next_back(), None);
1054 fn test_double_ended_range() {
1055 assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]);
1056 for _ in (10..0).rev() {
1057 panic!("unreachable");
1060 assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]);
1061 for _ in (10..0).rev() {
1062 panic!("unreachable");
1068 assert_eq!((0..5).collect::<Vec<_>>(), [0, 1, 2, 3, 4]);
1069 assert_eq!((-10..-1).collect::<Vec<_>>(), [-10, -9, -8, -7, -6, -5, -4, -3, -2]);
1070 assert_eq!((0..5).rev().collect::<Vec<_>>(), [4, 3, 2, 1, 0]);
1071 assert_eq!((200..-5).count(), 0);
1072 assert_eq!((200..-5).rev().count(), 0);
1073 assert_eq!((200..200).count(), 0);
1074 assert_eq!((200..200).rev().count(), 0);
1076 assert_eq!((0..100).size_hint(), (100, Some(100)));
1077 // this test is only meaningful when sizeof usize < sizeof u64
1078 assert_eq!((usize::MAX - 1..usize::MAX).size_hint(), (1, Some(1)));
1079 assert_eq!((-10..-1).size_hint(), (9, Some(9)));
1080 assert_eq!((-1..-10).size_hint(), (0, Some(0)));
1082 assert_eq!((-70..58).size_hint(), (128, Some(128)));
1083 assert_eq!((-128..127).size_hint(), (255, Some(255)));
1084 assert_eq!((-2..isize::MAX).size_hint(),
1085 (isize::MAX as usize + 2, Some(isize::MAX as usize + 2)));
1089 fn test_range_step() {
1090 #![allow(deprecated)]
1092 assert_eq!((0..20).step_by(5).collect::<Vec<isize>>(), [0, 5, 10, 15]);
1093 assert_eq!((20..0).step_by(-5).collect::<Vec<isize>>(), [20, 15, 10, 5]);
1094 assert_eq!((20..0).step_by(-6).collect::<Vec<isize>>(), [20, 14, 8, 2]);
1095 assert_eq!((200..255).step_by(50).collect::<Vec<u8>>(), [200, 250]);
1096 assert_eq!((200..-5).step_by(1).collect::<Vec<isize>>(), []);
1097 assert_eq!((200..200).step_by(1).collect::<Vec<isize>>(), []);
1099 assert_eq!((0..20).step_by(1).size_hint(), (20, Some(20)));
1100 assert_eq!((0..20).step_by(21).size_hint(), (1, Some(1)));
1101 assert_eq!((0..20).step_by(5).size_hint(), (4, Some(4)));
1102 assert_eq!((20..0).step_by(-5).size_hint(), (4, Some(4)));
1103 assert_eq!((20..0).step_by(-6).size_hint(), (4, Some(4)));
1104 assert_eq!((20..-5).step_by(1).size_hint(), (0, Some(0)));
1105 assert_eq!((20..20).step_by(1).size_hint(), (0, Some(0)));
1106 assert_eq!((0..1).step_by(0).size_hint(), (0, None));
1107 assert_eq!((i8::MAX..i8::MIN).step_by(i8::MIN).size_hint(), (2, Some(2)));
1108 assert_eq!((i16::MIN..i16::MAX).step_by(i16::MAX).size_hint(), (3, Some(3)));
1109 assert_eq!((isize::MIN..isize::MAX).step_by(1).size_hint(), (usize::MAX, Some(usize::MAX)));
1114 let mut it = repeat(42);
1115 assert_eq!(it.next(), Some(42));
1116 assert_eq!(it.next(), Some(42));
1117 assert_eq!(it.next(), Some(42));
1123 assert_eq!(it.len(), 3);
1124 assert_eq!(it.next(), Some(0));
1125 assert_eq!(it.len(), 2);
1126 assert_eq!(it.next(), Some(1));
1127 assert_eq!(it.len(), 1);
1128 assert_eq!(it.next(), Some(2));
1129 assert_eq!(it.len(), 0);
1130 assert_eq!(it.next(), None);
1131 assert_eq!(it.len(), 0);
1132 assert_eq!(it.next(), None);
1133 assert_eq!(it.len(), 0);
1134 assert_eq!(it.next(), None);
1135 assert_eq!(it.len(), 0);
1139 fn test_fuse_nth() {
1141 let mut it = xs.iter();
1143 assert_eq!(it.len(), 3);
1144 assert_eq!(it.nth(2), Some(&2));
1145 assert_eq!(it.len(), 0);
1146 assert_eq!(it.nth(2), None);
1147 assert_eq!(it.len(), 0);
1151 fn test_fuse_last() {
1155 assert_eq!(it.len(), 3);
1156 assert_eq!(it.last(), Some(&2));
1160 fn test_fuse_count() {
1164 assert_eq!(it.len(), 3);
1165 assert_eq!(it.count(), 3);
1166 // Can't check len now because count consumes.
1171 let mut it = once(42);
1172 assert_eq!(it.next(), Some(42));
1173 assert_eq!(it.next(), None);
1178 let mut it = empty::<i32>();
1179 assert_eq!(it.next(), None);
1183 fn test_chain_fold() {
1187 let mut iter = xs.iter().chain(&ys);
1189 let mut result = Vec::new();
1190 iter.fold((), |(), &elt| result.push(elt));
1191 assert_eq!(&[2, 3, 1, 2, 0], &result[..]);
1195 fn test_step_replace_unsigned() {
1197 let y = x.replace_zero();
1202 let y = x.replace_one();
1208 fn test_step_replace_signed() {
1210 let y = x.replace_zero();
1215 let y = x.replace_one();
1221 fn test_step_replace_no_between() {
1223 let y = x.replace_zero();
1228 let y = x.replace_one();