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Raymond Hettinger756b3f32004-01-29 06:37:52 +00001from collections import deque
2import unittest
Walter Dörwald09a3f2c2005-03-22 22:43:28 +00003from test import test_support, seq_tests
Raymond Hettinger691d8052004-05-30 07:26:47 +00004from weakref import proxy
Raymond Hettinger756b3f32004-01-29 06:37:52 +00005import copy
6import cPickle as pickle
7from cStringIO import StringIO
Raymond Hettinger0a4977c2004-03-01 23:16:22 +00008import random
Raymond Hettingera435c532004-07-09 04:10:20 +00009import os
Raymond Hettinger756b3f32004-01-29 06:37:52 +000010
11BIG = 100000
12
Raymond Hettingera435c532004-07-09 04:10:20 +000013def fail():
14 raise SyntaxError
15 yield 1
16
Raymond Hettinger4aec61e2005-03-18 21:20:23 +000017class BadCmp:
18 def __eq__(self, other):
19 raise RuntimeError
20
21class MutateCmp:
Raymond Hettingerd73202c2005-03-19 00:00:51 +000022 def __init__(self, deque, result):
Raymond Hettinger4aec61e2005-03-18 21:20:23 +000023 self.deque = deque
Raymond Hettingerd73202c2005-03-19 00:00:51 +000024 self.result = result
Raymond Hettinger4aec61e2005-03-18 21:20:23 +000025 def __eq__(self, other):
26 self.deque.clear()
Raymond Hettingerd73202c2005-03-19 00:00:51 +000027 return self.result
Raymond Hettinger4aec61e2005-03-18 21:20:23 +000028
Raymond Hettinger756b3f32004-01-29 06:37:52 +000029class TestBasic(unittest.TestCase):
30
31 def test_basics(self):
Raymond Hettingeradf9ffd2007-12-13 00:08:37 +000032 d = deque(xrange(-5125, -5000))
33 d.__init__(xrange(200))
Raymond Hettinger756b3f32004-01-29 06:37:52 +000034 for i in xrange(200, 400):
35 d.append(i)
36 for i in reversed(xrange(-200, 0)):
37 d.appendleft(i)
38 self.assertEqual(list(d), range(-200, 400))
39 self.assertEqual(len(d), 600)
40
41 left = [d.popleft() for i in xrange(250)]
42 self.assertEqual(left, range(-200, 50))
43 self.assertEqual(list(d), range(50, 400))
44
45 right = [d.pop() for i in xrange(250)]
46 right.reverse()
47 self.assertEqual(right, range(150, 400))
48 self.assertEqual(list(d), range(50, 150))
49
Raymond Hettingera7fc4b12007-10-05 02:47:07 +000050 def test_maxlen(self):
Raymond Hettinger68995862007-10-10 00:26:46 +000051 self.assertRaises(ValueError, deque, 'abc', -1)
Raymond Hettingera7fc4b12007-10-05 02:47:07 +000052 self.assertRaises(ValueError, deque, 'abc', -2)
53 d = deque(range(10), maxlen=3)
54 self.assertEqual(repr(d), 'deque([7, 8, 9], maxlen=3)')
55 self.assertEqual(list(d), range(7, 10))
56 self.assertEqual(d, deque(range(10), 3))
57 d.append(10)
58 self.assertEqual(list(d), range(8, 11))
59 d.appendleft(7)
60 self.assertEqual(list(d), range(7, 10))
61 d.extend([10, 11])
62 self.assertEqual(list(d), range(9, 12))
63 d.extendleft([8, 7])
64 self.assertEqual(list(d), range(7, 10))
65 d = deque(xrange(200), maxlen=10)
66 d.append(d)
67 try:
68 fo = open(test_support.TESTFN, "wb")
69 print >> fo, d,
70 fo.close()
71 fo = open(test_support.TESTFN, "rb")
72 self.assertEqual(fo.read(), repr(d))
73 finally:
74 fo.close()
75 os.remove(test_support.TESTFN)
76
Raymond Hettinger68995862007-10-10 00:26:46 +000077 d = deque(range(10), maxlen=None)
Raymond Hettingera7fc4b12007-10-05 02:47:07 +000078 self.assertEqual(repr(d), 'deque([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])')
79 try:
80 fo = open(test_support.TESTFN, "wb")
81 print >> fo, d,
82 fo.close()
83 fo = open(test_support.TESTFN, "rb")
84 self.assertEqual(fo.read(), repr(d))
85 finally:
86 fo.close()
87 os.remove(test_support.TESTFN)
88
Raymond Hettinger738ec902004-02-29 02:15:56 +000089 def test_comparisons(self):
90 d = deque('xabc'); d.popleft()
91 for e in [d, deque('abc'), deque('ab'), deque(), list(d)]:
92 self.assertEqual(d==e, type(d)==type(e) and list(d)==list(e))
93 self.assertEqual(d!=e, not(type(d)==type(e) and list(d)==list(e)))
94
95 args = map(deque, ('', 'a', 'b', 'ab', 'ba', 'abc', 'xba', 'xabc', 'cba'))
96 for x in args:
97 for y in args:
98 self.assertEqual(x == y, list(x) == list(y), (x,y))
99 self.assertEqual(x != y, list(x) != list(y), (x,y))
100 self.assertEqual(x < y, list(x) < list(y), (x,y))
101 self.assertEqual(x <= y, list(x) <= list(y), (x,y))
102 self.assertEqual(x > y, list(x) > list(y), (x,y))
103 self.assertEqual(x >= y, list(x) >= list(y), (x,y))
104 self.assertEqual(cmp(x,y), cmp(list(x),list(y)), (x,y))
105
Raymond Hettinger3ba85c22004-02-06 19:04:56 +0000106 def test_extend(self):
107 d = deque('a')
108 self.assertRaises(TypeError, d.extend, 1)
109 d.extend('bcd')
110 self.assertEqual(list(d), list('abcd'))
111
112 def test_extendleft(self):
113 d = deque('a')
114 self.assertRaises(TypeError, d.extendleft, 1)
115 d.extendleft('bcd')
116 self.assertEqual(list(d), list(reversed('abcd')))
Raymond Hettingera435c532004-07-09 04:10:20 +0000117 d = deque()
118 d.extendleft(range(1000))
119 self.assertEqual(list(d), list(reversed(range(1000))))
120 self.assertRaises(SyntaxError, d.extendleft, fail())
Raymond Hettinger3ba85c22004-02-06 19:04:56 +0000121
Raymond Hettinger0a4977c2004-03-01 23:16:22 +0000122 def test_getitem(self):
123 n = 200
124 d = deque(xrange(n))
125 l = range(n)
126 for i in xrange(n):
127 d.popleft()
128 l.pop(0)
129 if random.random() < 0.5:
130 d.append(i)
131 l.append(i)
132 for j in xrange(1-len(l), len(l)):
133 assert d[j] == l[j]
134
Raymond Hettinger738ec902004-02-29 02:15:56 +0000135 d = deque('superman')
Raymond Hettinger0a4977c2004-03-01 23:16:22 +0000136 self.assertEqual(d[0], 's')
137 self.assertEqual(d[-1], 'n')
Raymond Hettinger738ec902004-02-29 02:15:56 +0000138 d = deque()
Raymond Hettinger0a4977c2004-03-01 23:16:22 +0000139 self.assertRaises(IndexError, d.__getitem__, 0)
140 self.assertRaises(IndexError, d.__getitem__, -1)
141
142 def test_setitem(self):
143 n = 200
144 d = deque(xrange(n))
145 for i in xrange(n):
146 d[i] = 10 * i
147 self.assertEqual(list(d), [10*i for i in xrange(n)])
148 l = list(d)
149 for i in xrange(1-n, 0, -1):
150 d[i] = 7*i
151 l[i] = 7*i
152 self.assertEqual(list(d), l)
Raymond Hettinger738ec902004-02-29 02:15:56 +0000153
Raymond Hettinger0e371f22004-05-12 20:55:56 +0000154 def test_delitem(self):
155 n = 500 # O(n**2) test, don't make this too big
156 d = deque(xrange(n))
157 self.assertRaises(IndexError, d.__delitem__, -n-1)
158 self.assertRaises(IndexError, d.__delitem__, n)
159 for i in xrange(n):
160 self.assertEqual(len(d), n-i)
161 j = random.randrange(-len(d), len(d))
162 val = d[j]
163 self.assert_(val in d)
164 del d[j]
165 self.assert_(val not in d)
166 self.assertEqual(len(d), 0)
167
Raymond Hettinger5c5eb862004-02-07 21:13:00 +0000168 def test_rotate(self):
Raymond Hettingeree33b272004-02-08 04:05:26 +0000169 s = tuple('abcde')
170 n = len(s)
171
Raymond Hettinger5c5eb862004-02-07 21:13:00 +0000172 d = deque(s)
Raymond Hettingeree33b272004-02-08 04:05:26 +0000173 d.rotate(1) # verify rot(1)
174 self.assertEqual(''.join(d), 'eabcd')
175
176 d = deque(s)
177 d.rotate(-1) # verify rot(-1)
178 self.assertEqual(''.join(d), 'bcdea')
179 d.rotate() # check default to 1
180 self.assertEqual(tuple(d), s)
181
182 for i in xrange(n*3):
183 d = deque(s)
184 e = deque(d)
185 d.rotate(i) # check vs. rot(1) n times
186 for j in xrange(i):
187 e.rotate(1)
188 self.assertEqual(tuple(d), tuple(e))
189 d.rotate(-i) # check that it works in reverse
190 self.assertEqual(tuple(d), s)
191 e.rotate(n-i) # check that it wraps forward
192 self.assertEqual(tuple(e), s)
193
194 for i in xrange(n*3):
195 d = deque(s)
196 e = deque(d)
197 d.rotate(-i)
198 for j in xrange(i):
199 e.rotate(-1) # check vs. rot(-1) n times
200 self.assertEqual(tuple(d), tuple(e))
201 d.rotate(i) # check that it works in reverse
202 self.assertEqual(tuple(d), s)
203 e.rotate(i-n) # check that it wraps backaround
204 self.assertEqual(tuple(e), s)
205
206 d = deque(s)
207 e = deque(s)
208 e.rotate(BIG+17) # verify on long series of rotates
209 dr = d.rotate
210 for i in xrange(BIG+17):
211 dr()
212 self.assertEqual(tuple(d), tuple(e))
Raymond Hettinger5c5eb862004-02-07 21:13:00 +0000213
Raymond Hettingera435c532004-07-09 04:10:20 +0000214 self.assertRaises(TypeError, d.rotate, 'x') # Wrong arg type
215 self.assertRaises(TypeError, d.rotate, 1, 10) # Too many args
216
217 d = deque()
218 d.rotate() # rotate an empty deque
219 self.assertEqual(d, deque())
220
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000221 def test_len(self):
222 d = deque('ab')
223 self.assertEqual(len(d), 2)
224 d.popleft()
225 self.assertEqual(len(d), 1)
226 d.pop()
227 self.assertEqual(len(d), 0)
Raymond Hettinger738ec902004-02-29 02:15:56 +0000228 self.assertRaises(IndexError, d.pop)
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000229 self.assertEqual(len(d), 0)
230 d.append('c')
231 self.assertEqual(len(d), 1)
232 d.appendleft('d')
233 self.assertEqual(len(d), 2)
234 d.clear()
235 self.assertEqual(len(d), 0)
236
237 def test_underflow(self):
238 d = deque()
Raymond Hettinger738ec902004-02-29 02:15:56 +0000239 self.assertRaises(IndexError, d.pop)
240 self.assertRaises(IndexError, d.popleft)
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000241
242 def test_clear(self):
243 d = deque(xrange(100))
244 self.assertEqual(len(d), 100)
245 d.clear()
246 self.assertEqual(len(d), 0)
247 self.assertEqual(list(d), [])
Raymond Hettingera435c532004-07-09 04:10:20 +0000248 d.clear() # clear an emtpy deque
249 self.assertEqual(list(d), [])
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000250
Raymond Hettinger4aec61e2005-03-18 21:20:23 +0000251 def test_remove(self):
252 d = deque('abcdefghcij')
253 d.remove('c')
254 self.assertEqual(d, deque('abdefghcij'))
255 d.remove('c')
256 self.assertEqual(d, deque('abdefghij'))
257 self.assertRaises(ValueError, d.remove, 'c')
258 self.assertEqual(d, deque('abdefghij'))
259
Walter Dörwaldc448a912005-03-22 11:22:38 +0000260 # Handle comparison errors
Raymond Hettinger4aec61e2005-03-18 21:20:23 +0000261 d = deque(['a', 'b', BadCmp(), 'c'])
262 e = deque(d)
263 self.assertRaises(RuntimeError, d.remove, 'c')
264 for x, y in zip(d, e):
265 # verify that original order and values are retained.
266 self.assert_(x is y)
267
268 # Handle evil mutator
Raymond Hettingerd73202c2005-03-19 00:00:51 +0000269 for match in (True, False):
270 d = deque(['ab'])
271 d.extend([MutateCmp(d, match), 'c'])
272 self.assertRaises(IndexError, d.remove, 'c')
273 self.assertEqual(d, deque())
Raymond Hettinger4aec61e2005-03-18 21:20:23 +0000274
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000275 def test_repr(self):
276 d = deque(xrange(200))
277 e = eval(repr(d))
278 self.assertEqual(list(d), list(e))
279 d.append(d)
280 self.assert_('...' in repr(d))
281
282 def test_print(self):
283 d = deque(xrange(200))
284 d.append(d)
Raymond Hettingera435c532004-07-09 04:10:20 +0000285 try:
286 fo = open(test_support.TESTFN, "wb")
287 print >> fo, d,
288 fo.close()
289 fo = open(test_support.TESTFN, "rb")
290 self.assertEqual(fo.read(), repr(d))
291 finally:
292 fo.close()
293 os.remove(test_support.TESTFN)
294
295 def test_init(self):
Raymond Hettingera7fc4b12007-10-05 02:47:07 +0000296 self.assertRaises(TypeError, deque, 'abc', 2, 3);
Raymond Hettingera435c532004-07-09 04:10:20 +0000297 self.assertRaises(TypeError, deque, 1);
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000298
299 def test_hash(self):
300 self.assertRaises(TypeError, hash, deque('abc'))
301
302 def test_long_steadystate_queue_popleft(self):
303 for size in (0, 1, 2, 100, 1000):
304 d = deque(xrange(size))
305 append, pop = d.append, d.popleft
306 for i in xrange(size, BIG):
307 append(i)
308 x = pop()
309 if x != i - size:
310 self.assertEqual(x, i-size)
311 self.assertEqual(list(d), range(BIG-size, BIG))
312
313 def test_long_steadystate_queue_popright(self):
314 for size in (0, 1, 2, 100, 1000):
315 d = deque(reversed(xrange(size)))
316 append, pop = d.appendleft, d.pop
317 for i in xrange(size, BIG):
318 append(i)
319 x = pop()
320 if x != i - size:
321 self.assertEqual(x, i-size)
322 self.assertEqual(list(reversed(list(d))), range(BIG-size, BIG))
323
324 def test_big_queue_popleft(self):
325 pass
326 d = deque()
327 append, pop = d.append, d.popleft
328 for i in xrange(BIG):
329 append(i)
330 for i in xrange(BIG):
331 x = pop()
332 if x != i:
333 self.assertEqual(x, i)
334
335 def test_big_queue_popright(self):
336 d = deque()
337 append, pop = d.appendleft, d.pop
338 for i in xrange(BIG):
339 append(i)
340 for i in xrange(BIG):
341 x = pop()
342 if x != i:
343 self.assertEqual(x, i)
344
345 def test_big_stack_right(self):
346 d = deque()
347 append, pop = d.append, d.pop
348 for i in xrange(BIG):
349 append(i)
350 for i in reversed(xrange(BIG)):
351 x = pop()
352 if x != i:
353 self.assertEqual(x, i)
354 self.assertEqual(len(d), 0)
355
356 def test_big_stack_left(self):
357 d = deque()
358 append, pop = d.appendleft, d.popleft
359 for i in xrange(BIG):
360 append(i)
361 for i in reversed(xrange(BIG)):
362 x = pop()
363 if x != i:
364 self.assertEqual(x, i)
365 self.assertEqual(len(d), 0)
366
367 def test_roundtrip_iter_init(self):
368 d = deque(xrange(200))
369 e = deque(d)
370 self.assertNotEqual(id(d), id(e))
371 self.assertEqual(list(d), list(e))
372
373 def test_pickle(self):
374 d = deque(xrange(200))
Raymond Hettinger952f8802004-11-09 07:27:35 +0000375 for i in (0, 1, 2):
376 s = pickle.dumps(d, i)
377 e = pickle.loads(s)
378 self.assertNotEqual(id(d), id(e))
379 self.assertEqual(list(d), list(e))
380
Raymond Hettingera7fc4b12007-10-05 02:47:07 +0000381## def test_pickle_recursive(self):
382## d = deque('abc')
383## d.append(d)
384## for i in (0, 1, 2):
385## e = pickle.loads(pickle.dumps(d, i))
386## self.assertNotEqual(id(d), id(e))
387## self.assertEqual(id(e), id(e[-1]))
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000388
389 def test_deepcopy(self):
390 mut = [10]
391 d = deque([mut])
392 e = copy.deepcopy(d)
393 self.assertEqual(list(d), list(e))
394 mut[0] = 11
395 self.assertNotEqual(id(d), id(e))
396 self.assertNotEqual(list(d), list(e))
397
398 def test_copy(self):
399 mut = [10]
400 d = deque([mut])
401 e = copy.copy(d)
402 self.assertEqual(list(d), list(e))
403 mut[0] = 11
404 self.assertNotEqual(id(d), id(e))
405 self.assertEqual(list(d), list(e))
406
Raymond Hettingerc058fd12004-02-07 02:45:22 +0000407 def test_reversed(self):
408 for s in ('abcd', xrange(2000)):
409 self.assertEqual(list(reversed(deque(s))), list(reversed(s)))
410
Tim Peters10c7e862004-10-01 02:01:04 +0000411 def test_gc_doesnt_blowup(self):
412 import gc
413 # This used to assert-fail in deque_traverse() under a debug
414 # build, or run wild with a NULL pointer in a release build.
415 d = deque()
416 for i in xrange(100):
417 d.append(1)
418 gc.collect()
419
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000420class TestVariousIteratorArgs(unittest.TestCase):
421
422 def test_constructor(self):
423 for s in ("123", "", range(1000), ('do', 1.2), xrange(2000,2200,5)):
Walter Dörwald09a3f2c2005-03-22 22:43:28 +0000424 for g in (seq_tests.Sequence, seq_tests.IterFunc,
425 seq_tests.IterGen, seq_tests.IterFuncStop,
426 seq_tests.itermulti, seq_tests.iterfunc):
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000427 self.assertEqual(list(deque(g(s))), list(g(s)))
Walter Dörwald09a3f2c2005-03-22 22:43:28 +0000428 self.assertRaises(TypeError, deque, seq_tests.IterNextOnly(s))
429 self.assertRaises(TypeError, deque, seq_tests.IterNoNext(s))
430 self.assertRaises(ZeroDivisionError, deque, seq_tests.IterGenExc(s))
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000431
432 def test_iter_with_altered_data(self):
433 d = deque('abcdefg')
434 it = iter(d)
435 d.pop()
436 self.assertRaises(RuntimeError, it.next)
437
Raymond Hettinger51c2f6c2007-01-08 18:09:20 +0000438 def test_runtime_error_on_empty_deque(self):
439 d = deque()
440 it = iter(d)
441 d.append(10)
442 self.assertRaises(RuntimeError, it.next)
443
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000444class Deque(deque):
445 pass
446
Raymond Hettinger952f8802004-11-09 07:27:35 +0000447class DequeWithBadIter(deque):
448 def __iter__(self):
449 raise TypeError
450
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000451class TestSubclass(unittest.TestCase):
452
453 def test_basics(self):
Raymond Hettingeradf9ffd2007-12-13 00:08:37 +0000454 d = Deque(xrange(25))
455 d.__init__(xrange(200))
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000456 for i in xrange(200, 400):
457 d.append(i)
458 for i in reversed(xrange(-200, 0)):
459 d.appendleft(i)
460 self.assertEqual(list(d), range(-200, 400))
461 self.assertEqual(len(d), 600)
462
463 left = [d.popleft() for i in xrange(250)]
464 self.assertEqual(left, range(-200, 50))
465 self.assertEqual(list(d), range(50, 400))
466
467 right = [d.pop() for i in xrange(250)]
468 right.reverse()
469 self.assertEqual(right, range(150, 400))
470 self.assertEqual(list(d), range(50, 150))
471
472 d.clear()
473 self.assertEqual(len(d), 0)
474
475 def test_copy_pickle(self):
476
477 d = Deque('abc')
478
479 e = d.__copy__()
480 self.assertEqual(type(d), type(e))
481 self.assertEqual(list(d), list(e))
482
483 e = Deque(d)
484 self.assertEqual(type(d), type(e))
485 self.assertEqual(list(d), list(e))
486
487 s = pickle.dumps(d)
488 e = pickle.loads(s)
489 self.assertNotEqual(id(d), id(e))
490 self.assertEqual(type(d), type(e))
491 self.assertEqual(list(d), list(e))
492
Raymond Hettinger68995862007-10-10 00:26:46 +0000493 d = Deque('abcde', maxlen=4)
494
495 e = d.__copy__()
496 self.assertEqual(type(d), type(e))
497 self.assertEqual(list(d), list(e))
498
499 e = Deque(d)
500 self.assertEqual(type(d), type(e))
501 self.assertEqual(list(d), list(e))
502
503 s = pickle.dumps(d)
504 e = pickle.loads(s)
505 self.assertNotEqual(id(d), id(e))
506 self.assertEqual(type(d), type(e))
507 self.assertEqual(list(d), list(e))
508
Raymond Hettingera7fc4b12007-10-05 02:47:07 +0000509## def test_pickle(self):
510## d = Deque('abc')
511## d.append(d)
512##
513## e = pickle.loads(pickle.dumps(d))
514## self.assertNotEqual(id(d), id(e))
515## self.assertEqual(type(d), type(e))
516## dd = d.pop()
517## ee = e.pop()
518## self.assertEqual(id(e), id(ee))
519## self.assertEqual(d, e)
520##
521## d.x = d
522## e = pickle.loads(pickle.dumps(d))
523## self.assertEqual(id(e), id(e.x))
524##
525## d = DequeWithBadIter('abc')
526## self.assertRaises(TypeError, pickle.dumps, d)
Raymond Hettinger952f8802004-11-09 07:27:35 +0000527
Raymond Hettinger691d8052004-05-30 07:26:47 +0000528 def test_weakref(self):
529 d = deque('gallahad')
530 p = proxy(d)
531 self.assertEqual(str(p), str(d))
532 d = None
533 self.assertRaises(ReferenceError, str, p)
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000534
Armin Rigo974d7572004-10-02 13:59:34 +0000535 def test_strange_subclass(self):
536 class X(deque):
537 def __iter__(self):
538 return iter([])
539 d1 = X([1,2,3])
540 d2 = X([4,5,6])
541 d1 == d2 # not clear if this is supposed to be True or False,
542 # but it used to give a SystemError
543
Georg Brandlb84c1372007-01-21 10:28:43 +0000544
545class SubclassWithKwargs(deque):
546 def __init__(self, newarg=1):
547 deque.__init__(self)
548
549class TestSubclassWithKwargs(unittest.TestCase):
550 def test_subclass_with_kwargs(self):
551 # SF bug #1486663 -- this used to erroneously raise a TypeError
552 SubclassWithKwargs(newarg=1)
553
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000554#==============================================================================
555
Raymond Hettinger738ec902004-02-29 02:15:56 +0000556libreftest = """
557Example from the Library Reference: Doc/lib/libcollections.tex
558
559>>> from collections import deque
560>>> d = deque('ghi') # make a new deque with three items
561>>> for elem in d: # iterate over the deque's elements
Raymond Hettinger0a4977c2004-03-01 23:16:22 +0000562... print elem.upper()
Raymond Hettinger738ec902004-02-29 02:15:56 +0000563G
564H
565I
566>>> d.append('j') # add a new entry to the right side
567>>> d.appendleft('f') # add a new entry to the left side
568>>> d # show the representation of the deque
569deque(['f', 'g', 'h', 'i', 'j'])
570>>> d.pop() # return and remove the rightmost item
571'j'
572>>> d.popleft() # return and remove the leftmost item
573'f'
574>>> list(d) # list the contents of the deque
575['g', 'h', 'i']
Raymond Hettinger0a4977c2004-03-01 23:16:22 +0000576>>> d[0] # peek at leftmost item
Raymond Hettinger738ec902004-02-29 02:15:56 +0000577'g'
Raymond Hettinger0a4977c2004-03-01 23:16:22 +0000578>>> d[-1] # peek at rightmost item
Raymond Hettinger738ec902004-02-29 02:15:56 +0000579'i'
580>>> list(reversed(d)) # list the contents of a deque in reverse
581['i', 'h', 'g']
582>>> 'h' in d # search the deque
583True
584>>> d.extend('jkl') # add multiple elements at once
585>>> d
586deque(['g', 'h', 'i', 'j', 'k', 'l'])
587>>> d.rotate(1) # right rotation
588>>> d
589deque(['l', 'g', 'h', 'i', 'j', 'k'])
590>>> d.rotate(-1) # left rotation
591>>> d
592deque(['g', 'h', 'i', 'j', 'k', 'l'])
593>>> deque(reversed(d)) # make a new deque in reverse order
594deque(['l', 'k', 'j', 'i', 'h', 'g'])
595>>> d.clear() # empty the deque
596>>> d.pop() # cannot pop from an empty deque
597Traceback (most recent call last):
598 File "<pyshell#6>", line 1, in -toplevel-
599 d.pop()
600IndexError: pop from an empty deque
601
602>>> d.extendleft('abc') # extendleft() reverses the input order
603>>> d
604deque(['c', 'b', 'a'])
605
Raymond Hettingere7169eb2004-05-09 01:15:01 +0000606
607
Raymond Hettingere7169eb2004-05-09 01:15:01 +0000608>>> def delete_nth(d, n):
Raymond Hettingere7169eb2004-05-09 01:15:01 +0000609... d.rotate(-n)
610... d.popleft()
611... d.rotate(n)
612...
613>>> d = deque('abcdef')
614>>> delete_nth(d, 2) # remove the entry at d[2]
615>>> d
616deque(['a', 'b', 'd', 'e', 'f'])
617
618
619
620>>> def roundrobin(*iterables):
621... pending = deque(iter(i) for i in iterables)
622... while pending:
623... task = pending.popleft()
624... try:
625... yield task.next()
626... except StopIteration:
627... continue
628... pending.append(task)
629...
630
631>>> for value in roundrobin('abc', 'd', 'efgh'):
632... print value
633...
634a
635d
636e
637b
638f
639c
640g
641h
642
643
644>>> def maketree(iterable):
645... d = deque(iterable)
646... while len(d) > 1:
647... pair = [d.popleft(), d.popleft()]
648... d.append(pair)
649... return list(d)
650...
651>>> print maketree('abcdefgh')
652[[[['a', 'b'], ['c', 'd']], [['e', 'f'], ['g', 'h']]]]
653
Raymond Hettinger738ec902004-02-29 02:15:56 +0000654"""
655
656
657#==============================================================================
658
659__test__ = {'libreftest' : libreftest}
660
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000661def test_main(verbose=None):
662 import sys
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000663 test_classes = (
664 TestBasic,
665 TestVariousIteratorArgs,
666 TestSubclass,
Georg Brandlb84c1372007-01-21 10:28:43 +0000667 TestSubclassWithKwargs,
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000668 )
669
670 test_support.run_unittest(*test_classes)
671
672 # verify reference counting
673 if verbose and hasattr(sys, "gettotalrefcount"):
674 import gc
675 counts = [None] * 5
676 for i in xrange(len(counts)):
677 test_support.run_unittest(*test_classes)
678 gc.collect()
679 counts[i] = sys.gettotalrefcount()
680 print counts
Raymond Hettinger0a4977c2004-03-01 23:16:22 +0000681
Raymond Hettinger738ec902004-02-29 02:15:56 +0000682 # doctests
683 from test import test_deque
Raymond Hettinger354433a2004-05-19 08:20:33 +0000684 test_support.run_doctest(test_deque, verbose)
Raymond Hettinger756b3f32004-01-29 06:37:52 +0000685
686if __name__ == "__main__":
687 test_main(verbose=True)