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::iter::order::*;
13 use core::{i8, i16, isize};
20 let empty: [isize; 0] = [];
24 assert!(!lt(xs.iter(), ys.iter()));
25 assert!(!le(xs.iter(), ys.iter()));
26 assert!( gt(xs.iter(), ys.iter()));
27 assert!( ge(xs.iter(), ys.iter()));
29 assert!( lt(ys.iter(), xs.iter()));
30 assert!( le(ys.iter(), xs.iter()));
31 assert!(!gt(ys.iter(), xs.iter()));
32 assert!(!ge(ys.iter(), xs.iter()));
34 assert!( lt(empty.iter(), xs.iter()));
35 assert!( le(empty.iter(), xs.iter()));
36 assert!(!gt(empty.iter(), xs.iter()));
37 assert!(!ge(empty.iter(), xs.iter()));
40 let u = [1.0f64, 2.0];
41 let v = [0.0f64/0.0, 3.0];
43 assert!(!lt(u.iter(), v.iter()));
44 assert!(!le(u.iter(), v.iter()));
45 assert!(!gt(u.iter(), v.iter()));
46 assert!(!ge(u.iter(), v.iter()));
52 assert!(lt(a.iter(), b.iter()) == (a[0] < b[0]));
53 assert!(le(a.iter(), b.iter()) == (a[0] <= b[0]));
54 assert!(gt(a.iter(), b.iter()) == (a[0] > b[0]));
55 assert!(ge(a.iter(), b.iter()) == (a[0] >= b[0]));
57 assert!(lt(c.iter(), b.iter()) == (c[0] < b[0]));
58 assert!(le(c.iter(), b.iter()) == (c[0] <= b[0]));
59 assert!(gt(c.iter(), b.iter()) == (c[0] > b[0]));
60 assert!(ge(c.iter(), b.iter()) == (c[0] >= b[0]));
64 fn test_multi_iter() {
67 assert!(eq(xs.iter(), ys.iter().rev()));
68 assert!(lt(xs.iter(), xs.iter().skip(2)));
72 fn test_counter_from_iter() {
73 let it = (0..).step_by(5).take(10);
74 let xs: Vec<isize> = FromIterator::from_iter(it);
75 assert_eq!(xs, [0, 5, 10, 15, 20, 25, 30, 35, 40, 45]);
79 fn test_iterator_chain() {
80 let xs = [0, 1, 2, 3, 4, 5];
81 let ys = [30, 40, 50, 60];
82 let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
83 let it = xs.iter().chain(&ys);
86 assert_eq!(x, expected[i]);
89 assert_eq!(i, expected.len());
91 let ys = (30..).step_by(10).take(4);
92 let it = xs.iter().cloned().chain(ys);
95 assert_eq!(x, expected[i]);
98 assert_eq!(i, expected.len());
102 fn test_iterator_chain_nth() {
103 let xs = [0, 1, 2, 3, 4, 5];
104 let ys = [30, 40, 50, 60];
106 let expected = [0, 1, 2, 3, 4, 5, 30, 40, 50, 60];
107 for (i, x) in expected.iter().enumerate() {
108 assert_eq!(Some(x), xs.iter().chain(&ys).nth(i));
110 assert_eq!(zs.iter().chain(&xs).nth(0), Some(&0));
112 let mut it = xs.iter().chain(&zs);
113 assert_eq!(it.nth(5), Some(&5));
114 assert_eq!(it.next(), None);
118 fn test_iterator_chain_last() {
119 let xs = [0, 1, 2, 3, 4, 5];
120 let ys = [30, 40, 50, 60];
122 assert_eq!(xs.iter().chain(&ys).last(), Some(&60));
123 assert_eq!(zs.iter().chain(&ys).last(), Some(&60));
124 assert_eq!(ys.iter().chain(&zs).last(), Some(&60));
125 assert_eq!(zs.iter().chain(&zs).last(), None);
129 fn test_iterator_chain_count() {
130 let xs = [0, 1, 2, 3, 4, 5];
131 let ys = [30, 40, 50, 60];
133 assert_eq!(xs.iter().chain(&ys).count(), 10);
134 assert_eq!(zs.iter().chain(&ys).count(), 4);
138 fn test_filter_map() {
139 let it = (0..).step_by(1).take(10)
140 .filter_map(|x| if x % 2 == 0 { Some(x*x) } else { None });
141 assert_eq!(it.collect::<Vec<usize>>(), [0*0, 2*2, 4*4, 6*6, 8*8]);
145 fn test_iterator_enumerate() {
146 let xs = [0, 1, 2, 3, 4, 5];
147 let it = xs.iter().enumerate();
154 fn test_iterator_enumerate_nth() {
155 let xs = [0, 1, 2, 3, 4, 5];
156 for (i, &x) in xs.iter().enumerate() {
160 let mut it = xs.iter().enumerate();
161 while let Some((i, &x)) = it.nth(0) {
165 let mut it = xs.iter().enumerate();
166 while let Some((i, &x)) = it.nth(1) {
170 let (i, &x) = xs.iter().enumerate().nth(3).unwrap();
176 fn test_iterator_enumerate_count() {
177 let xs = [0, 1, 2, 3, 4, 5];
178 assert_eq!(xs.iter().count(), 6);
182 fn test_iterator_peekable() {
183 let xs = vec![0, 1, 2, 3, 4, 5];
184 let mut it = xs.iter().cloned().peekable();
186 assert_eq!(it.len(), 6);
187 assert_eq!(it.peek().unwrap(), &0);
188 assert_eq!(it.len(), 6);
189 assert_eq!(it.next().unwrap(), 0);
190 assert_eq!(it.len(), 5);
191 assert_eq!(it.next().unwrap(), 1);
192 assert_eq!(it.len(), 4);
193 assert_eq!(it.next().unwrap(), 2);
194 assert_eq!(it.len(), 3);
195 assert_eq!(it.peek().unwrap(), &3);
196 assert_eq!(it.len(), 3);
197 assert_eq!(it.peek().unwrap(), &3);
198 assert_eq!(it.len(), 3);
199 assert_eq!(it.next().unwrap(), 3);
200 assert_eq!(it.len(), 2);
201 assert_eq!(it.next().unwrap(), 4);
202 assert_eq!(it.len(), 1);
203 assert_eq!(it.peek().unwrap(), &5);
204 assert_eq!(it.len(), 1);
205 assert_eq!(it.next().unwrap(), 5);
206 assert_eq!(it.len(), 0);
207 assert!(it.peek().is_none());
208 assert_eq!(it.len(), 0);
209 assert!(it.next().is_none());
210 assert_eq!(it.len(), 0);
214 fn test_iterator_peekable_count() {
215 let xs = [0, 1, 2, 3, 4, 5];
217 let zs: [i32; 0] = [];
219 assert_eq!(xs.iter().peekable().count(), 6);
221 let mut it = xs.iter().peekable();
222 assert_eq!(it.peek(), Some(&&0));
223 assert_eq!(it.count(), 6);
225 assert_eq!(ys.iter().peekable().count(), 1);
227 let mut it = ys.iter().peekable();
228 assert_eq!(it.peek(), Some(&&10));
229 assert_eq!(it.count(), 1);
231 assert_eq!(zs.iter().peekable().count(), 0);
233 let mut it = zs.iter().peekable();
234 assert_eq!(it.peek(), None);
239 fn test_iterator_peekable_nth() {
240 let xs = [0, 1, 2, 3, 4, 5];
241 let mut it = xs.iter().peekable();
243 assert_eq!(it.peek(), Some(&&0));
244 assert_eq!(it.nth(0), Some(&0));
245 assert_eq!(it.peek(), Some(&&1));
246 assert_eq!(it.nth(1), Some(&2));
247 assert_eq!(it.peek(), Some(&&3));
248 assert_eq!(it.nth(2), Some(&5));
249 assert_eq!(it.next(), None);
253 fn test_iterator_peekable_last() {
254 let xs = [0, 1, 2, 3, 4, 5];
257 let mut it = xs.iter().peekable();
258 assert_eq!(it.peek(), Some(&&0));
259 assert_eq!(it.last(), Some(&5));
261 let mut it = ys.iter().peekable();
262 assert_eq!(it.peek(), Some(&&0));
263 assert_eq!(it.last(), Some(&0));
267 fn test_iterator_take_while() {
268 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
269 let ys = [0, 1, 2, 3, 5, 13];
270 let it = xs.iter().take_while(|&x| *x < 15);
273 assert_eq!(*x, ys[i]);
276 assert_eq!(i, ys.len());
280 fn test_iterator_skip_while() {
281 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
282 let ys = [15, 16, 17, 19];
283 let it = xs.iter().skip_while(|&x| *x < 15);
286 assert_eq!(*x, ys[i]);
289 assert_eq!(i, ys.len());
293 fn test_iterator_skip() {
294 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
295 let ys = [13, 15, 16, 17, 19, 20, 30];
296 let mut it = xs.iter().skip(5);
298 while let Some(&x) = it.next() {
299 assert_eq!(x, ys[i]);
301 assert_eq!(it.len(), xs.len()-5-i);
303 assert_eq!(i, ys.len());
304 assert_eq!(it.len(), 0);
308 fn test_iterator_skip_nth() {
309 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
311 let mut it = xs.iter().skip(0);
312 assert_eq!(it.nth(0), Some(&0));
313 assert_eq!(it.nth(1), Some(&2));
315 let mut it = xs.iter().skip(5);
316 assert_eq!(it.nth(0), Some(&13));
317 assert_eq!(it.nth(1), Some(&16));
319 let mut it = xs.iter().skip(12);
320 assert_eq!(it.nth(0), None);
325 fn test_iterator_skip_count() {
326 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
328 assert_eq!(xs.iter().skip(0).count(), 12);
329 assert_eq!(xs.iter().skip(1).count(), 11);
330 assert_eq!(xs.iter().skip(11).count(), 1);
331 assert_eq!(xs.iter().skip(12).count(), 0);
332 assert_eq!(xs.iter().skip(13).count(), 0);
336 fn test_iterator_skip_last() {
337 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19, 20, 30];
339 assert_eq!(xs.iter().skip(0).last(), Some(&30));
340 assert_eq!(xs.iter().skip(1).last(), Some(&30));
341 assert_eq!(xs.iter().skip(11).last(), Some(&30));
342 assert_eq!(xs.iter().skip(12).last(), None);
343 assert_eq!(xs.iter().skip(13).last(), None);
345 let mut it = xs.iter().skip(5);
346 assert_eq!(it.next(), Some(&13));
347 assert_eq!(it.last(), Some(&30));
351 fn test_iterator_take() {
352 let xs = [0, 1, 2, 3, 5, 13, 15, 16, 17, 19];
353 let ys = [0, 1, 2, 3, 5];
354 let mut it = xs.iter().take(5);
356 assert_eq!(it.len(), 5);
357 while let Some(&x) = it.next() {
358 assert_eq!(x, ys[i]);
360 assert_eq!(it.len(), 5-i);
362 assert_eq!(i, ys.len());
363 assert_eq!(it.len(), 0);
367 fn test_iterator_take_nth() {
368 let xs = [0, 1, 2, 4, 5];
369 let mut it = xs.iter();
371 let mut take = it.by_ref().take(3);
373 while let Some(&x) = take.nth(0) {
378 assert_eq!(it.nth(1), Some(&5));
379 assert_eq!(it.nth(0), None);
381 let xs = [0, 1, 2, 3, 4];
382 let mut it = xs.iter().take(7);
384 while let Some(&x) = it.nth(1) {
391 fn test_iterator_take_short() {
392 let xs = [0, 1, 2, 3];
393 let ys = [0, 1, 2, 3];
394 let mut it = xs.iter().take(5);
396 assert_eq!(it.len(), 4);
397 while let Some(&x) = it.next() {
398 assert_eq!(x, ys[i]);
400 assert_eq!(it.len(), 4-i);
402 assert_eq!(i, ys.len());
403 assert_eq!(it.len(), 0);
407 fn test_iterator_scan() {
408 // test the type inference
409 fn add(old: &mut isize, new: &usize) -> Option<f64> {
410 *old += *new as isize;
413 let xs = [0, 1, 2, 3, 4];
414 let ys = [0f64, 1.0, 3.0, 6.0, 10.0];
416 let it = xs.iter().scan(0, add);
419 assert_eq!(x, ys[i]);
422 assert_eq!(i, ys.len());
426 fn test_iterator_flat_map() {
428 let ys = [0, 1, 2, 3, 4, 5, 6, 7, 8];
429 let it = xs.iter().flat_map(|&x| (x..).step_by(1).take(3));
432 assert_eq!(x, ys[i]);
435 assert_eq!(i, ys.len());
440 let xs = [1, 2, 3, 4];
446 .collect::<Vec<usize>>();
448 assert_eq!(n, xs.len());
449 assert_eq!(&xs[..], &ys[..]);
455 let it = (0..).step_by(1).take(cycle_len).cycle();
456 assert_eq!(it.size_hint(), (usize::MAX, None));
457 for (i, x) in it.take(100).enumerate() {
458 assert_eq!(i % cycle_len, x);
461 let mut it = (0..).step_by(1).take(0).cycle();
462 assert_eq!(it.size_hint(), (0, Some(0)));
463 assert_eq!(it.next(), None);
467 fn test_iterator_nth() {
468 let v: &[_] = &[0, 1, 2, 3, 4];
469 for i in 0..v.len() {
470 assert_eq!(v.iter().nth(i).unwrap(), &v[i]);
472 assert_eq!(v.iter().nth(v.len()), None);
476 fn test_iterator_last() {
477 let v: &[_] = &[0, 1, 2, 3, 4];
478 assert_eq!(v.iter().last().unwrap(), &4);
479 assert_eq!(v[..1].iter().last().unwrap(), &0);
483 fn test_iterator_len() {
484 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
485 assert_eq!(v[..4].iter().count(), 4);
486 assert_eq!(v[..10].iter().count(), 10);
487 assert_eq!(v[..0].iter().count(), 0);
491 fn test_iterator_sum() {
492 let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
493 assert_eq!(v[..4].iter().cloned().sum::<i32>(), 6);
494 assert_eq!(v.iter().cloned().sum::<i32>(), 55);
495 assert_eq!(v[..0].iter().cloned().sum::<i32>(), 0);
499 fn test_iterator_product() {
500 let v: &[i32] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
501 assert_eq!(v[..4].iter().cloned().product::<i32>(), 0);
502 assert_eq!(v[1..5].iter().cloned().product::<i32>(), 24);
503 assert_eq!(v[..0].iter().cloned().product::<i32>(), 1);
507 fn test_iterator_max() {
508 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
509 assert_eq!(v[..4].iter().cloned().max(), Some(3));
510 assert_eq!(v.iter().cloned().max(), Some(10));
511 assert_eq!(v[..0].iter().cloned().max(), None);
515 fn test_iterator_min() {
516 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10];
517 assert_eq!(v[..4].iter().cloned().min(), Some(0));
518 assert_eq!(v.iter().cloned().min(), Some(0));
519 assert_eq!(v[..0].iter().cloned().min(), None);
523 fn test_iterator_size_hint() {
524 let c = (0..).step_by(1);
525 let v: &[_] = &[0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
526 let v2 = &[10, 11, 12];
529 assert_eq!(c.size_hint(), (usize::MAX, None));
530 assert_eq!(vi.clone().size_hint(), (10, Some(10)));
532 assert_eq!(c.clone().take(5).size_hint(), (5, Some(5)));
533 assert_eq!(c.clone().skip(5).size_hint().1, None);
534 assert_eq!(c.clone().take_while(|_| false).size_hint(), (0, None));
535 assert_eq!(c.clone().skip_while(|_| false).size_hint(), (0, None));
536 assert_eq!(c.clone().enumerate().size_hint(), (usize::MAX, None));
537 assert_eq!(c.clone().chain(vi.clone().cloned()).size_hint(), (usize::MAX, None));
538 assert_eq!(c.clone().zip(vi.clone()).size_hint(), (10, Some(10)));
539 assert_eq!(c.clone().scan(0, |_,_| Some(0)).size_hint(), (0, None));
540 assert_eq!(c.clone().filter(|_| false).size_hint(), (0, None));
541 assert_eq!(c.clone().map(|_| 0).size_hint(), (usize::MAX, None));
542 assert_eq!(c.filter_map(|_| Some(0)).size_hint(), (0, None));
544 assert_eq!(vi.clone().take(5).size_hint(), (5, Some(5)));
545 assert_eq!(vi.clone().take(12).size_hint(), (10, Some(10)));
546 assert_eq!(vi.clone().skip(3).size_hint(), (7, Some(7)));
547 assert_eq!(vi.clone().skip(12).size_hint(), (0, Some(0)));
548 assert_eq!(vi.clone().take_while(|_| false).size_hint(), (0, Some(10)));
549 assert_eq!(vi.clone().skip_while(|_| false).size_hint(), (0, Some(10)));
550 assert_eq!(vi.clone().enumerate().size_hint(), (10, Some(10)));
551 assert_eq!(vi.clone().chain(v2).size_hint(), (13, Some(13)));
552 assert_eq!(vi.clone().zip(v2).size_hint(), (3, Some(3)));
553 assert_eq!(vi.clone().scan(0, |_,_| Some(0)).size_hint(), (0, Some(10)));
554 assert_eq!(vi.clone().filter(|_| false).size_hint(), (0, Some(10)));
555 assert_eq!(vi.clone().map(|&i| i+1).size_hint(), (10, Some(10)));
556 assert_eq!(vi.filter_map(|_| Some(0)).size_hint(), (0, Some(10)));
561 let a = vec![1, 2, 3, 4, 5];
562 let b: Vec<isize> = a.iter().cloned().collect();
568 // FIXME (#22405): Replace `Box::new` with `box` here when/if possible.
569 let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
570 assert!(v.iter().all(|&x| x < 10));
571 assert!(!v.iter().all(|&x| x % 2 == 0));
572 assert!(!v.iter().all(|&x| x > 100));
573 assert!(v[..0].iter().all(|_| panic!()));
578 // FIXME (#22405): Replace `Box::new` with `box` here when/if possible.
579 let v: Box<[isize]> = Box::new([1, 2, 3, 4, 5]);
580 assert!(v.iter().any(|&x| x < 10));
581 assert!(v.iter().any(|&x| x % 2 == 0));
582 assert!(!v.iter().any(|&x| x > 100));
583 assert!(!v[..0].iter().any(|_| panic!()));
588 let v: &[isize] = &[1, 3, 9, 27, 103, 14, 11];
589 assert_eq!(*v.iter().find(|&&x| x & 1 == 0).unwrap(), 14);
590 assert_eq!(*v.iter().find(|&&x| x % 3 == 0).unwrap(), 3);
591 assert!(v.iter().find(|&&x| x % 12 == 0).is_none());
596 let v = &[1, 3, 9, 27, 103, 14, 11];
597 assert_eq!(v.iter().position(|x| *x & 1 == 0).unwrap(), 5);
598 assert_eq!(v.iter().position(|x| *x % 3 == 0).unwrap(), 1);
599 assert!(v.iter().position(|x| *x % 12 == 0).is_none());
604 let xs = &[1, 2, 2, 1, 5, 9, 0, 2];
605 assert_eq!(xs.iter().filter(|x| **x == 2).count(), 3);
606 assert_eq!(xs.iter().filter(|x| **x == 5).count(), 1);
607 assert_eq!(xs.iter().filter(|x| **x == 95).count(), 0);
612 let xs: &[isize] = &[-3, 0, 1, 5, -10];
613 assert_eq!(*xs.iter().max_by(|x| x.abs()).unwrap(), -10);
618 let xs: &[isize] = &[-3, 0, 1, 5, -10];
619 assert_eq!(*xs.iter().min_by(|x| x.abs()).unwrap(), 0);
625 // sum the first five values
626 let partial_sum = xs.by_ref().take(5).fold(0, |a, b| a + b);
627 assert_eq!(partial_sum, 10);
628 assert_eq!(xs.next(), Some(5));
633 let xs = [2, 4, 6, 8, 10, 12, 14, 16];
634 let mut it = xs.iter();
637 assert!(it.rev().cloned().collect::<Vec<isize>>() ==
638 vec![16, 14, 12, 10, 8, 6]);
643 let xs = [2u8, 4, 6, 8];
645 let mut it = xs.iter().cloned();
646 assert_eq!(it.len(), 4);
647 assert_eq!(it.next(), Some(2));
648 assert_eq!(it.len(), 3);
649 assert_eq!(it.next(), Some(4));
650 assert_eq!(it.len(), 2);
651 assert_eq!(it.next_back(), Some(8));
652 assert_eq!(it.len(), 1);
653 assert_eq!(it.next_back(), Some(6));
654 assert_eq!(it.len(), 0);
655 assert_eq!(it.next_back(), None);
659 fn test_double_ended_map() {
660 let xs = [1, 2, 3, 4, 5, 6];
661 let mut it = xs.iter().map(|&x| x * -1);
662 assert_eq!(it.next(), Some(-1));
663 assert_eq!(it.next(), Some(-2));
664 assert_eq!(it.next_back(), Some(-6));
665 assert_eq!(it.next_back(), Some(-5));
666 assert_eq!(it.next(), Some(-3));
667 assert_eq!(it.next_back(), Some(-4));
668 assert_eq!(it.next(), None);
672 fn test_double_ended_enumerate() {
673 let xs = [1, 2, 3, 4, 5, 6];
674 let mut it = xs.iter().cloned().enumerate();
675 assert_eq!(it.next(), Some((0, 1)));
676 assert_eq!(it.next(), Some((1, 2)));
677 assert_eq!(it.next_back(), Some((5, 6)));
678 assert_eq!(it.next_back(), Some((4, 5)));
679 assert_eq!(it.next_back(), Some((3, 4)));
680 assert_eq!(it.next_back(), Some((2, 3)));
681 assert_eq!(it.next(), None);
685 fn test_double_ended_zip() {
686 let xs = [1, 2, 3, 4, 5, 6];
687 let ys = [1, 2, 3, 7];
688 let a = xs.iter().cloned();
689 let b = ys.iter().cloned();
690 let mut it = a.zip(b);
691 assert_eq!(it.next(), Some((1, 1)));
692 assert_eq!(it.next(), Some((2, 2)));
693 assert_eq!(it.next_back(), Some((4, 7)));
694 assert_eq!(it.next_back(), Some((3, 3)));
695 assert_eq!(it.next(), None);
699 fn test_double_ended_filter() {
700 let xs = [1, 2, 3, 4, 5, 6];
701 let mut it = xs.iter().filter(|&x| *x & 1 == 0);
702 assert_eq!(it.next_back().unwrap(), &6);
703 assert_eq!(it.next_back().unwrap(), &4);
704 assert_eq!(it.next().unwrap(), &2);
705 assert_eq!(it.next_back(), None);
709 fn test_double_ended_filter_map() {
710 let xs = [1, 2, 3, 4, 5, 6];
711 let mut it = xs.iter().filter_map(|&x| if x & 1 == 0 { Some(x * 2) } else { None });
712 assert_eq!(it.next_back().unwrap(), 12);
713 assert_eq!(it.next_back().unwrap(), 8);
714 assert_eq!(it.next().unwrap(), 4);
715 assert_eq!(it.next_back(), None);
719 fn test_double_ended_chain() {
720 let xs = [1, 2, 3, 4, 5];
722 let mut it = xs.iter().chain(&ys).rev();
723 assert_eq!(it.next().unwrap(), &11);
724 assert_eq!(it.next().unwrap(), &9);
725 assert_eq!(it.next_back().unwrap(), &1);
726 assert_eq!(it.next_back().unwrap(), &2);
727 assert_eq!(it.next_back().unwrap(), &3);
728 assert_eq!(it.next_back().unwrap(), &4);
729 assert_eq!(it.next_back().unwrap(), &5);
730 assert_eq!(it.next_back().unwrap(), &7);
731 assert_eq!(it.next_back(), None);
735 fn test_rposition() {
736 fn f(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'b' }
737 fn g(xy: &(isize, char)) -> bool { let (_x, y) = *xy; y == 'd' }
738 let v = [(0, 'a'), (1, 'b'), (2, 'c'), (3, 'b')];
740 assert_eq!(v.iter().rposition(f), Some(3));
741 assert!(v.iter().rposition(g).is_none());
746 fn test_rposition_panic() {
747 let v: [(Box<_>, Box<_>); 4] =
748 [(box 0, box 0), (box 0, box 0),
749 (box 0, box 0), (box 0, box 0)];
751 v.iter().rposition(|_elt| {
762 fn test_double_ended_flat_map() {
765 let mut it = u.iter().flat_map(|x| &v[*x..v.len()]);
766 assert_eq!(it.next_back().unwrap(), &8);
767 assert_eq!(it.next().unwrap(), &5);
768 assert_eq!(it.next_back().unwrap(), &7);
769 assert_eq!(it.next_back().unwrap(), &6);
770 assert_eq!(it.next_back().unwrap(), &8);
771 assert_eq!(it.next().unwrap(), &6);
772 assert_eq!(it.next_back().unwrap(), &7);
773 assert_eq!(it.next_back(), None);
774 assert_eq!(it.next(), None);
775 assert_eq!(it.next_back(), None);
779 fn test_double_ended_range() {
780 assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]);
781 for _ in (10..0).rev() {
782 panic!("unreachable");
785 assert_eq!((11..14).rev().collect::<Vec<_>>(), [13, 12, 11]);
786 for _ in (10..0).rev() {
787 panic!("unreachable");
793 assert_eq!((0..5).collect::<Vec<_>>(), [0, 1, 2, 3, 4]);
794 assert_eq!((-10..-1).collect::<Vec<_>>(), [-10, -9, -8, -7, -6, -5, -4, -3, -2]);
795 assert_eq!((0..5).rev().collect::<Vec<_>>(), [4, 3, 2, 1, 0]);
796 assert_eq!((200..-5).count(), 0);
797 assert_eq!((200..-5).rev().count(), 0);
798 assert_eq!((200..200).count(), 0);
799 assert_eq!((200..200).rev().count(), 0);
801 assert_eq!((0..100).size_hint(), (100, Some(100)));
802 // this test is only meaningful when sizeof usize < sizeof u64
803 assert_eq!((usize::MAX - 1..usize::MAX).size_hint(), (1, Some(1)));
804 assert_eq!((-10..-1).size_hint(), (9, Some(9)));
805 assert_eq!((-1..-10).size_hint(), (0, Some(0)));
807 assert_eq!((-70..58i8).size_hint(), (128, Some(128)));
808 assert_eq!((-128..127i8).size_hint(), (255, Some(255)));
809 assert_eq!((-2..isize::MAX).size_hint(),
810 (isize::MAX as usize + 2, Some(isize::MAX as usize + 2)));
814 fn test_range_inclusive() {
815 assert!(range_inclusive(0, 5).collect::<Vec<isize>>() ==
816 vec![0, 1, 2, 3, 4, 5]);
817 assert!(range_inclusive(0, 5).rev().collect::<Vec<isize>>() ==
818 vec![5, 4, 3, 2, 1, 0]);
819 assert_eq!(range_inclusive(200, -5).count(), 0);
820 assert_eq!(range_inclusive(200, -5).rev().count(), 0);
821 assert_eq!(range_inclusive(200, 200).collect::<Vec<isize>>(), [200]);
822 assert_eq!(range_inclusive(200, 200).rev().collect::<Vec<isize>>(), [200]);
826 fn test_range_step() {
827 assert_eq!((0..20).step_by(5).collect::<Vec<isize>>(), [0, 5, 10, 15]);
828 assert_eq!((20..0).step_by(-5).collect::<Vec<isize>>(), [20, 15, 10, 5]);
829 assert_eq!((20..0).step_by(-6).collect::<Vec<isize>>(), [20, 14, 8, 2]);
830 assert_eq!((200..255).step_by(50).collect::<Vec<u8>>(), [200, 250]);
831 assert_eq!((200..-5).step_by(1).collect::<Vec<isize>>(), []);
832 assert_eq!((200..200).step_by(1).collect::<Vec<isize>>(), []);
834 assert_eq!((0..20).step_by(1).size_hint(), (20, Some(20)));
835 assert_eq!((0..20).step_by(21).size_hint(), (1, Some(1)));
836 assert_eq!((0..20).step_by(5).size_hint(), (4, Some(4)));
837 assert_eq!((20..0).step_by(-5).size_hint(), (4, Some(4)));
838 assert_eq!((20..0).step_by(-6).size_hint(), (4, Some(4)));
839 assert_eq!((20..-5).step_by(1).size_hint(), (0, Some(0)));
840 assert_eq!((20..20).step_by(1).size_hint(), (0, Some(0)));
841 assert_eq!((0..1).step_by(0).size_hint(), (0, None));
842 assert_eq!((i8::MAX..i8::MIN).step_by(i8::MIN).size_hint(), (2, Some(2)));
843 assert_eq!((i16::MIN..i16::MAX).step_by(i16::MAX).size_hint(), (3, Some(3)));
844 assert_eq!((isize::MIN..isize::MAX).step_by(1).size_hint(), (usize::MAX, Some(usize::MAX)));
848 fn test_peekable_is_empty() {
850 let mut it = a.iter().peekable();
851 assert!( !it.is_empty() );
853 assert!( it.is_empty() );
858 let mut it = repeat(42);
859 assert_eq!(it.next(), Some(42));
860 assert_eq!(it.next(), Some(42));
861 assert_eq!(it.next(), Some(42));
867 assert_eq!(it.len(), 3);
868 assert_eq!(it.next(), Some(0));
869 assert_eq!(it.len(), 2);
870 assert_eq!(it.next(), Some(1));
871 assert_eq!(it.len(), 1);
872 assert_eq!(it.next(), Some(2));
873 assert_eq!(it.len(), 0);
874 assert_eq!(it.next(), None);
875 assert_eq!(it.len(), 0);
876 assert_eq!(it.next(), None);
877 assert_eq!(it.len(), 0);
878 assert_eq!(it.next(), None);
879 assert_eq!(it.len(), 0);
885 let mut it = xs.iter();
887 assert_eq!(it.len(), 3);
888 assert_eq!(it.nth(2), Some(&2));
889 assert_eq!(it.len(), 0);
890 assert_eq!(it.nth(2), None);
891 assert_eq!(it.len(), 0);
895 fn test_fuse_last() {
899 assert_eq!(it.len(), 3);
900 assert_eq!(it.last(), Some(&2));
904 fn test_fuse_count() {
908 assert_eq!(it.len(), 3);
909 assert_eq!(it.count(), 3);
910 // Can't check len now because count consumes.
915 let mut it = once(42);
916 assert_eq!(it.next(), Some(42));
917 assert_eq!(it.next(), None);
922 let mut it = empty::<i32>();
923 assert_eq!(it.next(), None);
927 fn bench_rposition(b: &mut Bencher) {
928 let it: Vec<usize> = (0..300).collect();
930 it.iter().rposition(|&x| x <= 150);
935 fn bench_skip_while(b: &mut Bencher) {
939 it.skip_while(|&x| { sum += x; sum < 4000 }).all(|_| true);
944 fn bench_multiple_take(b: &mut Bencher) {
945 let mut it = (0..42).cycle();
947 let n = it.next().unwrap();
949 it.clone().take(it.next().unwrap()).all(|_| true);
954 fn scatter(x: i32) -> i32 { (x * 31) % 127 }
957 fn bench_max_by(b: &mut Bencher) {
960 it.max_by(|&x| scatter(x))
964 // http://www.reddit.com/r/rust/comments/31syce/using_iterators_to_find_the_index_of_the_min_or/
966 fn bench_max_by2(b: &mut Bencher) {
967 fn max_index_iter(array: &[i32]) -> usize {
968 array.iter().enumerate().max_by(|&(_, item)| item).unwrap().0
971 let mut data = vec![0i32; 1638];
974 b.iter(|| max_index_iter(&data));
978 fn bench_max(b: &mut Bencher) {
981 it.map(scatter).max()