{{ message }}
-
Notifications
You must be signed in to change notification settings - Fork 12
Expand file tree
/
Copy pathdatastructures.po
More file actions
1006 lines (881 loc) · 31.8 KB
/
Copy pathdatastructures.po
File metadata and controls
1006 lines (881 loc) · 31.8 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
# SOME DESCRIPTIVE TITLE.
# Copyright (C) 2001 Python Software Foundation
# This file is distributed under the same license as the Python package.
# FIRST AUTHOR <EMAIL@ADDRESS>, YEAR.
#
# Translators:
# Alireza Shabani (Revisto) <theRevisto@gmail.com>, 2025
#
#, fuzzy
msgid ""
msgstr ""
"Project-Id-Version: Python 3.14\n"
"Report-Msgid-Bugs-To: \n"
"POT-Creation-Date: 2025-07-11 14:21+0000\n"
"PO-Revision-Date: 2021-06-28 01:50+0000\n"
"Last-Translator: Alireza Shabani (Revisto) <theRevisto@gmail.com>, 2025\n"
"Language-Team: Persian (https://app.transifex.com/python-doc/teams/5390/"
"fa/)\n"
"MIME-Version: 1.0\n"
"Content-Type: text/plain; charset=UTF-8\n"
"Content-Transfer-Encoding: 8bit\n"
"Language: fa\n"
"Plural-Forms: nplurals=2; plural=(n > 1);\n"
#: ../../tutorial/datastructures.rst:5
msgid "Data Structures"
msgstr ""
#: ../../tutorial/datastructures.rst:7
msgid ""
"This chapter describes some things you've learned about already in more "
"detail, and adds some new things as well."
msgstr ""
#: ../../tutorial/datastructures.rst:13
msgid "More on Lists"
msgstr ""
#: ../../tutorial/datastructures.rst:15
msgid ""
"The list data type has some more methods. Here are all of the methods of "
"list objects:"
msgstr ""
#: ../../tutorial/datastructures.rst:22
msgid "Add an item to the end of the list. Similar to ``a[len(a):] = [x]``."
msgstr ""
#: ../../tutorial/datastructures.rst:28
msgid ""
"Extend the list by appending all the items from the iterable. Similar to "
"``a[len(a):] = iterable``."
msgstr ""
#: ../../tutorial/datastructures.rst:35
msgid ""
"Insert an item at a given position. The first argument is the index of the "
"element before which to insert, so ``a.insert(0, x)`` inserts at the front "
"of the list, and ``a.insert(len(a), x)`` is equivalent to ``a.append(x)``."
msgstr ""
#: ../../tutorial/datastructures.rst:43
msgid ""
"Remove the first item from the list whose value is equal to *x*. It raises "
"a :exc:`ValueError` if there is no such item."
msgstr ""
#: ../../tutorial/datastructures.rst:50
msgid ""
"Remove the item at the given position in the list, and return it. If no "
"index is specified, ``a.pop()`` removes and returns the last item in the "
"list. It raises an :exc:`IndexError` if the list is empty or the index is "
"outside the list range."
msgstr ""
#: ../../tutorial/datastructures.rst:59
msgid "Remove all items from the list. Similar to ``del a[:]``."
msgstr ""
#: ../../tutorial/datastructures.rst:65
msgid ""
"Return zero-based index in the list of the first item whose value is equal "
"to *x*. Raises a :exc:`ValueError` if there is no such item."
msgstr ""
#: ../../tutorial/datastructures.rst:68
msgid ""
"The optional arguments *start* and *end* are interpreted as in the slice "
"notation and are used to limit the search to a particular subsequence of the "
"list. The returned index is computed relative to the beginning of the full "
"sequence rather than the *start* argument."
msgstr ""
#: ../../tutorial/datastructures.rst:77
msgid "Return the number of times *x* appears in the list."
msgstr ""
#: ../../tutorial/datastructures.rst:83
msgid ""
"Sort the items of the list in place (the arguments can be used for sort "
"customization, see :func:`sorted` for their explanation)."
msgstr ""
#: ../../tutorial/datastructures.rst:90
msgid "Reverse the elements of the list in place."
msgstr ""
#: ../../tutorial/datastructures.rst:96
msgid "Return a shallow copy of the list. Similar to ``a[:]``."
msgstr ""
#: ../../tutorial/datastructures.rst:99
msgid "An example that uses most of the list methods::"
msgstr ""
#: ../../tutorial/datastructures.rst:101
msgid ""
">>> fruits = ['orange', 'apple', 'pear', 'banana', 'kiwi', 'apple', "
"'banana']\n"
">>> fruits.count('apple')\n"
"2\n"
">>> fruits.count('tangerine')\n"
"0\n"
">>> fruits.index('banana')\n"
"3\n"
">>> fruits.index('banana', 4) # Find next banana starting at position 4\n"
"6\n"
">>> fruits.reverse()\n"
">>> fruits\n"
"['banana', 'apple', 'kiwi', 'banana', 'pear', 'apple', 'orange']\n"
">>> fruits.append('grape')\n"
">>> fruits\n"
"['banana', 'apple', 'kiwi', 'banana', 'pear', 'apple', 'orange', 'grape']\n"
">>> fruits.sort()\n"
">>> fruits\n"
"['apple', 'apple', 'banana', 'banana', 'grape', 'kiwi', 'orange', 'pear']\n"
">>> fruits.pop()\n"
"'pear'"
msgstr ""
#: ../../tutorial/datastructures.rst:122
msgid ""
"You might have noticed that methods like ``insert``, ``remove`` or ``sort`` "
"that only modify the list have no return value printed -- they return the "
"default ``None``. [#]_ This is a design principle for all mutable data "
"structures in Python."
msgstr ""
#: ../../tutorial/datastructures.rst:127
msgid ""
"Another thing you might notice is that not all data can be sorted or "
"compared. For instance, ``[None, 'hello', 10]`` doesn't sort because "
"integers can't be compared to strings and ``None`` can't be compared to "
"other types. Also, there are some types that don't have a defined ordering "
"relation. For example, ``3+4j < 5+7j`` isn't a valid comparison."
msgstr ""
#: ../../tutorial/datastructures.rst:138
msgid "Using Lists as Stacks"
msgstr ""
#: ../../tutorial/datastructures.rst:143
msgid ""
"The list methods make it very easy to use a list as a stack, where the last "
"element added is the first element retrieved (\"last-in, first-out\"). To "
"add an item to the top of the stack, use :meth:`!append`. To retrieve an "
"item from the top of the stack, use :meth:`!pop` without an explicit index. "
"For example::"
msgstr ""
#: ../../tutorial/datastructures.rst:148
msgid ""
">>> stack = [3, 4, 5]\n"
">>> stack.append(6)\n"
">>> stack.append(7)\n"
">>> stack\n"
"[3, 4, 5, 6, 7]\n"
">>> stack.pop()\n"
"7\n"
">>> stack\n"
"[3, 4, 5, 6]\n"
">>> stack.pop()\n"
"6\n"
">>> stack.pop()\n"
"5\n"
">>> stack\n"
"[3, 4]"
msgstr ""
#: ../../tutorial/datastructures.rst:168
msgid "Using Lists as Queues"
msgstr ""
#: ../../tutorial/datastructures.rst:172
msgid ""
"It is also possible to use a list as a queue, where the first element added "
"is the first element retrieved (\"first-in, first-out\"); however, lists are "
"not efficient for this purpose. While appends and pops from the end of list "
"are fast, doing inserts or pops from the beginning of a list is slow "
"(because all of the other elements have to be shifted by one)."
msgstr ""
#: ../../tutorial/datastructures.rst:178
msgid ""
"To implement a queue, use :class:`collections.deque` which was designed to "
"have fast appends and pops from both ends. For example::"
msgstr ""
#: ../../tutorial/datastructures.rst:181
msgid ""
">>> from collections import deque\n"
">>> queue = deque([\"Eric\", \"John\", \"Michael\"])\n"
">>> queue.append(\"Terry\") # Terry arrives\n"
">>> queue.append(\"Graham\") # Graham arrives\n"
">>> queue.popleft() # The first to arrive now leaves\n"
"'Eric'\n"
">>> queue.popleft() # The second to arrive now leaves\n"
"'John'\n"
">>> queue # Remaining queue in order of arrival\n"
"deque(['Michael', 'Terry', 'Graham'])"
msgstr ""
#: ../../tutorial/datastructures.rst:196
msgid "List Comprehensions"
msgstr ""
#: ../../tutorial/datastructures.rst:198
msgid ""
"List comprehensions provide a concise way to create lists. Common "
"applications are to make new lists where each element is the result of some "
"operations applied to each member of another sequence or iterable, or to "
"create a subsequence of those elements that satisfy a certain condition."
msgstr ""
#: ../../tutorial/datastructures.rst:203
msgid "For example, assume we want to create a list of squares, like::"
msgstr ""
#: ../../tutorial/datastructures.rst:205
msgid ""
">>> squares = []\n"
">>> for x in range(10):\n"
"... squares.append(x**2)\n"
"...\n"
">>> squares\n"
"[0, 1, 4, 9, 16, 25, 36, 49, 64, 81]"
msgstr ""
#: ../../tutorial/datastructures.rst:212
msgid ""
"Note that this creates (or overwrites) a variable named ``x`` that still "
"exists after the loop completes. We can calculate the list of squares "
"without any side effects using::"
msgstr ""
#: ../../tutorial/datastructures.rst:216
msgid "squares = list(map(lambda x: x**2, range(10)))"
msgstr ""
#: ../../tutorial/datastructures.rst:218
msgid "or, equivalently::"
msgstr ""
#: ../../tutorial/datastructures.rst:220
msgid "squares = [x**2 for x in range(10)]"
msgstr ""
#: ../../tutorial/datastructures.rst:222
msgid "which is more concise and readable."
msgstr ""
#: ../../tutorial/datastructures.rst:224
msgid ""
"A list comprehension consists of brackets containing an expression followed "
"by a :keyword:`!for` clause, then zero or more :keyword:`!for` or :keyword:`!"
"if` clauses. The result will be a new list resulting from evaluating the "
"expression in the context of the :keyword:`!for` and :keyword:`!if` clauses "
"which follow it. For example, this listcomp combines the elements of two "
"lists if they are not equal::"
msgstr ""
#: ../../tutorial/datastructures.rst:231
msgid ""
">>> [(x, y) for x in [1,2,3] for y in [3,1,4] if x != y]\n"
"[(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)]"
msgstr ""
#: ../../tutorial/datastructures.rst:234
msgid "and it's equivalent to::"
msgstr ""
#: ../../tutorial/datastructures.rst:236
msgid ""
">>> combs = []\n"
">>> for x in [1,2,3]:\n"
"... for y in [3,1,4]:\n"
"... if x != y:\n"
"... combs.append((x, y))\n"
"...\n"
">>> combs\n"
"[(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)]"
msgstr ""
#: ../../tutorial/datastructures.rst:245
msgid ""
"Note how the order of the :keyword:`for` and :keyword:`if` statements is the "
"same in both these snippets."
msgstr ""
#: ../../tutorial/datastructures.rst:248
msgid ""
"If the expression is a tuple (e.g. the ``(x, y)`` in the previous example), "
"it must be parenthesized. ::"
msgstr ""
#: ../../tutorial/datastructures.rst:251
msgid ""
">>> vec = [-4, -2, 0, 2, 4]\n"
">>> # create a new list with the values doubled\n"
">>> [x*2 for x in vec]\n"
"[-8, -4, 0, 4, 8]\n"
">>> # filter the list to exclude negative numbers\n"
">>> [x for x in vec if x >= 0]\n"
"[0, 2, 4]\n"
">>> # apply a function to all the elements\n"
">>> [abs(x) for x in vec]\n"
"[4, 2, 0, 2, 4]\n"
">>> # call a method on each element\n"
">>> freshfruit = [' banana', ' loganberry ', 'passion fruit ']\n"
">>> [weapon.strip() for weapon in freshfruit]\n"
"['banana', 'loganberry', 'passion fruit']\n"
">>> # create a list of 2-tuples like (number, square)\n"
">>> [(x, x**2) for x in range(6)]\n"
"[(0, 0), (1, 1), (2, 4), (3, 9), (4, 16), (5, 25)]\n"
">>> # the tuple must be parenthesized, otherwise an error is raised\n"
">>> [x, x**2 for x in range(6)]\n"
" File \"<stdin>\", line 1\n"
" [x, x**2 for x in range(6)]\n"
" ^^^^^^^\n"
"SyntaxError: did you forget parentheses around the comprehension target?\n"
">>> # flatten a list using a listcomp with two 'for'\n"
">>> vec = [[1,2,3], [4,5,6], [7,8,9]]\n"
">>> [num for elem in vec for num in elem]\n"
"[1, 2, 3, 4, 5, 6, 7, 8, 9]"
msgstr ""
#: ../../tutorial/datastructures.rst:279
msgid ""
"List comprehensions can contain complex expressions and nested functions::"
msgstr ""
#: ../../tutorial/datastructures.rst:281
msgid ""
">>> from math import pi\n"
">>> [str(round(pi, i)) for i in range(1, 6)]\n"
"['3.1', '3.14', '3.142', '3.1416', '3.14159']"
msgstr ""
#: ../../tutorial/datastructures.rst:286
msgid "Nested List Comprehensions"
msgstr ""
#: ../../tutorial/datastructures.rst:288
msgid ""
"The initial expression in a list comprehension can be any arbitrary "
"expression, including another list comprehension."
msgstr ""
#: ../../tutorial/datastructures.rst:291
msgid ""
"Consider the following example of a 3x4 matrix implemented as a list of 3 "
"lists of length 4::"
msgstr ""
#: ../../tutorial/datastructures.rst:294
msgid ""
">>> matrix = [\n"
"... [1, 2, 3, 4],\n"
"... [5, 6, 7, 8],\n"
"... [9, 10, 11, 12],\n"
"... ]"
msgstr ""
#: ../../tutorial/datastructures.rst:300
msgid "The following list comprehension will transpose rows and columns::"
msgstr ""
#: ../../tutorial/datastructures.rst:302
msgid ""
">>> [[row[i] for row in matrix] for i in range(4)]\n"
"[[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]"
msgstr ""
#: ../../tutorial/datastructures.rst:305
msgid ""
"As we saw in the previous section, the inner list comprehension is evaluated "
"in the context of the :keyword:`for` that follows it, so this example is "
"equivalent to::"
msgstr ""
#: ../../tutorial/datastructures.rst:309
msgid ""
">>> transposed = []\n"
">>> for i in range(4):\n"
"... transposed.append([row[i] for row in matrix])\n"
"...\n"
">>> transposed\n"
"[[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]"
msgstr ""
#: ../../tutorial/datastructures.rst:316
msgid "which, in turn, is the same as::"
msgstr ""
#: ../../tutorial/datastructures.rst:318
msgid ""
">>> transposed = []\n"
">>> for i in range(4):\n"
"... # the following 3 lines implement the nested listcomp\n"
"... transposed_row = []\n"
"... for row in matrix:\n"
"... transposed_row.append(row[i])\n"
"... transposed.append(transposed_row)\n"
"...\n"
">>> transposed\n"
"[[1, 5, 9], [2, 6, 10], [3, 7, 11], [4, 8, 12]]"
msgstr ""
#: ../../tutorial/datastructures.rst:329
msgid ""
"In the real world, you should prefer built-in functions to complex flow "
"statements. The :func:`zip` function would do a great job for this use case::"
msgstr ""
#: ../../tutorial/datastructures.rst:332
msgid ""
">>> list(zip(*matrix))\n"
"[(1, 5, 9), (2, 6, 10), (3, 7, 11), (4, 8, 12)]"
msgstr ""
#: ../../tutorial/datastructures.rst:335
msgid ""
"See :ref:`tut-unpacking-arguments` for details on the asterisk in this line."
msgstr ""
#: ../../tutorial/datastructures.rst:340
msgid "The :keyword:`!del` statement"
msgstr ""
#: ../../tutorial/datastructures.rst:342
msgid ""
"There is a way to remove an item from a list given its index instead of its "
"value: the :keyword:`del` statement. This differs from the :meth:`!pop` "
"method which returns a value. The :keyword:`!del` statement can also be "
"used to remove slices from a list or clear the entire list (which we did "
"earlier by assignment of an empty list to the slice). For example::"
msgstr ""
#: ../../tutorial/datastructures.rst:348
msgid ""
">>> a = [-1, 1, 66.25, 333, 333, 1234.5]\n"
">>> del a[0]\n"
">>> a\n"
"[1, 66.25, 333, 333, 1234.5]\n"
">>> del a[2:4]\n"
">>> a\n"
"[1, 66.25, 1234.5]\n"
">>> del a[:]\n"
">>> a\n"
"[]"
msgstr ""
#: ../../tutorial/datastructures.rst:359
msgid ":keyword:`del` can also be used to delete entire variables::"
msgstr ""
#: ../../tutorial/datastructures.rst:361
msgid ">>> del a"
msgstr ""
#: ../../tutorial/datastructures.rst:363
msgid ""
"Referencing the name ``a`` hereafter is an error (at least until another "
"value is assigned to it). We'll find other uses for :keyword:`del` later."
msgstr ""
#: ../../tutorial/datastructures.rst:370
msgid "Tuples and Sequences"
msgstr ""
#: ../../tutorial/datastructures.rst:372
msgid ""
"We saw that lists and strings have many common properties, such as indexing "
"and slicing operations. They are two examples of *sequence* data types "
"(see :ref:`typesseq`). Since Python is an evolving language, other sequence "
"data types may be added. There is also another standard sequence data type: "
"the *tuple*."
msgstr ""
#: ../../tutorial/datastructures.rst:378
msgid ""
"A tuple consists of a number of values separated by commas, for instance::"
msgstr ""
#: ../../tutorial/datastructures.rst:380
msgid ""
">>> t = 12345, 54321, 'hello!'\n"
">>> t[0]\n"
"12345\n"
">>> t\n"
"(12345, 54321, 'hello!')\n"
">>> # Tuples may be nested:\n"
">>> u = t, (1, 2, 3, 4, 5)\n"
">>> u\n"
"((12345, 54321, 'hello!'), (1, 2, 3, 4, 5))\n"
">>> # Tuples are immutable:\n"
">>> t[0] = 88888\n"
"Traceback (most recent call last):\n"
" File \"<stdin>\", line 1, in <module>\n"
"TypeError: 'tuple' object does not support item assignment\n"
">>> # but they can contain mutable objects:\n"
">>> v = ([1, 2, 3], [3, 2, 1])\n"
">>> v\n"
"([1, 2, 3], [3, 2, 1])"
msgstr ""
#: ../../tutorial/datastructures.rst:400
msgid ""
"As you see, on output tuples are always enclosed in parentheses, so that "
"nested tuples are interpreted correctly; they may be input with or without "
"surrounding parentheses, although often parentheses are necessary anyway (if "
"the tuple is part of a larger expression). It is not possible to assign to "
"the individual items of a tuple, however it is possible to create tuples "
"which contain mutable objects, such as lists."
msgstr ""
#: ../../tutorial/datastructures.rst:407
msgid ""
"Though tuples may seem similar to lists, they are often used in different "
"situations and for different purposes. Tuples are :term:`immutable`, and "
"usually contain a heterogeneous sequence of elements that are accessed via "
"unpacking (see later in this section) or indexing (or even by attribute in "
"the case of :func:`namedtuples <collections.namedtuple>`). Lists are :term:"
"`mutable`, and their elements are usually homogeneous and are accessed by "
"iterating over the list."
msgstr ""
#: ../../tutorial/datastructures.rst:415
msgid ""
"A special problem is the construction of tuples containing 0 or 1 items: the "
"syntax has some extra quirks to accommodate these. Empty tuples are "
"constructed by an empty pair of parentheses; a tuple with one item is "
"constructed by following a value with a comma (it is not sufficient to "
"enclose a single value in parentheses). Ugly, but effective. For example::"
msgstr ""
#: ../../tutorial/datastructures.rst:421
msgid ""
">>> empty = ()\n"
">>> singleton = 'hello', # <-- note trailing comma\n"
">>> len(empty)\n"
"0\n"
">>> len(singleton)\n"
"1\n"
">>> singleton\n"
"('hello',)"
msgstr ""
#: ../../tutorial/datastructures.rst:430
msgid ""
"The statement ``t = 12345, 54321, 'hello!'`` is an example of *tuple "
"packing*: the values ``12345``, ``54321`` and ``'hello!'`` are packed "
"together in a tuple. The reverse operation is also possible::"
msgstr ""
#: ../../tutorial/datastructures.rst:434
msgid ">>> x, y, z = t"
msgstr ""
#: ../../tutorial/datastructures.rst:436
msgid ""
"This is called, appropriately enough, *sequence unpacking* and works for any "
"sequence on the right-hand side. Sequence unpacking requires that there are "
"as many variables on the left side of the equals sign as there are elements "
"in the sequence. Note that multiple assignment is really just a combination "
"of tuple packing and sequence unpacking."
msgstr ""
#: ../../tutorial/datastructures.rst:446
msgid "Sets"
msgstr ""
#: ../../tutorial/datastructures.rst:448
msgid ""
"Python also includes a data type for *sets*. A set is an unordered "
"collection with no duplicate elements. Basic uses include membership "
"testing and eliminating duplicate entries. Set objects also support "
"mathematical operations like union, intersection, difference, and symmetric "
"difference."
msgstr ""
#: ../../tutorial/datastructures.rst:453
msgid ""
"Curly braces or the :func:`set` function can be used to create sets. Note: "
"to create an empty set you have to use ``set()``, not ``{}``; the latter "
"creates an empty dictionary, a data structure that we discuss in the next "
"section."
msgstr ""
#: ../../tutorial/datastructures.rst:457
msgid "Here is a brief demonstration::"
msgstr ""
#: ../../tutorial/datastructures.rst:459
msgid ""
">>> basket = {'apple', 'orange', 'apple', 'pear', 'orange', 'banana'}\n"
">>> print(basket) # show that duplicates have been "
"removed\n"
"{'orange', 'banana', 'pear', 'apple'}\n"
">>> 'orange' in basket # fast membership testing\n"
"True\n"
">>> 'crabgrass' in basket\n"
"False\n"
"\n"
">>> # Demonstrate set operations on unique letters from two words\n"
">>>\n"
">>> a = set('abracadabra')\n"
">>> b = set('alacazam')\n"
">>> a # unique letters in a\n"
"{'a', 'r', 'b', 'c', 'd'}\n"
">>> a - b # letters in a but not in b\n"
"{'r', 'd', 'b'}\n"
">>> a | b # letters in a or b or both\n"
"{'a', 'c', 'r', 'd', 'b', 'm', 'z', 'l'}\n"
">>> a & b # letters in both a and b\n"
"{'a', 'c'}\n"
">>> a ^ b # letters in a or b but not both\n"
"{'r', 'd', 'b', 'm', 'z', 'l'}"
msgstr ""
#: ../../tutorial/datastructures.rst:482
msgid ""
"Similarly to :ref:`list comprehensions <tut-listcomps>`, set comprehensions "
"are also supported::"
msgstr ""
#: ../../tutorial/datastructures.rst:485
msgid ""
">>> a = {x for x in 'abracadabra' if x not in 'abc'}\n"
">>> a\n"
"{'r', 'd'}"
msgstr ""
#: ../../tutorial/datastructures.rst:493
msgid "Dictionaries"
msgstr ""
#: ../../tutorial/datastructures.rst:495
msgid ""
"Another useful data type built into Python is the *dictionary* (see :ref:"
"`typesmapping`). Dictionaries are sometimes found in other languages as "
"\"associative memories\" or \"associative arrays\". Unlike sequences, which "
"are indexed by a range of numbers, dictionaries are indexed by *keys*, which "
"can be any immutable type; strings and numbers can always be keys. Tuples "
"can be used as keys if they contain only strings, numbers, or tuples; if a "
"tuple contains any mutable object either directly or indirectly, it cannot "
"be used as a key. You can't use lists as keys, since lists can be modified "
"in place using index assignments, slice assignments, or methods like :meth:`!"
"append` and :meth:`!extend`."
msgstr ""
#: ../../tutorial/datastructures.rst:506
msgid ""
"It is best to think of a dictionary as a set of *key: value* pairs, with the "
"requirement that the keys are unique (within one dictionary). A pair of "
"braces creates an empty dictionary: ``{}``. Placing a comma-separated list "
"of key:value pairs within the braces adds initial key:value pairs to the "
"dictionary; this is also the way dictionaries are written on output."
msgstr ""
#: ../../tutorial/datastructures.rst:512
msgid ""
"The main operations on a dictionary are storing a value with some key and "
"extracting the value given the key. It is also possible to delete a key:"
"value pair with ``del``. If you store using a key that is already in use, "
"the old value associated with that key is forgotten. It is an error to "
"extract a value using a non-existent key."
msgstr ""
#: ../../tutorial/datastructures.rst:518
msgid ""
"Performing ``list(d)`` on a dictionary returns a list of all the keys used "
"in the dictionary, in insertion order (if you want it sorted, just use "
"``sorted(d)`` instead). To check whether a single key is in the dictionary, "
"use the :keyword:`in` keyword."
msgstr ""
#: ../../tutorial/datastructures.rst:523
msgid "Here is a small example using a dictionary::"
msgstr ""
#: ../../tutorial/datastructures.rst:525
msgid ""
">>> tel = {'jack': 4098, 'sape': 4139}\n"
">>> tel['guido'] = 4127\n"
">>> tel\n"
"{'jack': 4098, 'sape': 4139, 'guido': 4127}\n"
">>> tel['jack']\n"
"4098\n"
">>> del tel['sape']\n"
">>> tel['irv'] = 4127\n"
">>> tel\n"
"{'jack': 4098, 'guido': 4127, 'irv': 4127}\n"
">>> list(tel)\n"
"['jack', 'guido', 'irv']\n"
">>> sorted(tel)\n"
"['guido', 'irv', 'jack']\n"
">>> 'guido' in tel\n"
"True\n"
">>> 'jack' not in tel\n"
"False"
msgstr ""
#: ../../tutorial/datastructures.rst:544
msgid ""
"The :func:`dict` constructor builds dictionaries directly from sequences of "
"key-value pairs::"
msgstr ""
#: ../../tutorial/datastructures.rst:547
msgid ""
">>> dict([('sape', 4139), ('guido', 4127), ('jack', 4098)])\n"
"{'sape': 4139, 'guido': 4127, 'jack': 4098}"
msgstr ""
#: ../../tutorial/datastructures.rst:550
msgid ""
"In addition, dict comprehensions can be used to create dictionaries from "
"arbitrary key and value expressions::"
msgstr ""
#: ../../tutorial/datastructures.rst:553
msgid ""
">>> {x: x**2 for x in (2, 4, 6)}\n"
"{2: 4, 4: 16, 6: 36}"
msgstr ""
#: ../../tutorial/datastructures.rst:556
msgid ""
"When the keys are simple strings, it is sometimes easier to specify pairs "
"using keyword arguments::"
msgstr ""
#: ../../tutorial/datastructures.rst:559
msgid ""
">>> dict(sape=4139, guido=4127, jack=4098)\n"
"{'sape': 4139, 'guido': 4127, 'jack': 4098}"
msgstr ""
#: ../../tutorial/datastructures.rst:566
msgid "Looping Techniques"
msgstr ""
#: ../../tutorial/datastructures.rst:568
msgid ""
"When looping through dictionaries, the key and corresponding value can be "
"retrieved at the same time using the :meth:`~dict.items` method. ::"
msgstr ""
#: ../../tutorial/datastructures.rst:571
msgid ""
">>> knights = {'gallahad': 'the pure', 'robin': 'the brave'}\n"
">>> for k, v in knights.items():\n"
"... print(k, v)\n"
"...\n"
"gallahad the pure\n"
"robin the brave"
msgstr ""
#: ../../tutorial/datastructures.rst:578
msgid ""
"When looping through a sequence, the position index and corresponding value "
"can be retrieved at the same time using the :func:`enumerate` function. ::"
msgstr ""
#: ../../tutorial/datastructures.rst:581
msgid ""
">>> for i, v in enumerate(['tic', 'tac', 'toe']):\n"
"... print(i, v)\n"
"...\n"
"0 tic\n"
"1 tac\n"
"2 toe"
msgstr ""
#: ../../tutorial/datastructures.rst:588
msgid ""
"To loop over two or more sequences at the same time, the entries can be "
"paired with the :func:`zip` function. ::"
msgstr ""
#: ../../tutorial/datastructures.rst:591
msgid ""
">>> questions = ['name', 'quest', 'favorite color']\n"
">>> answers = ['lancelot', 'the holy grail', 'blue']\n"
">>> for q, a in zip(questions, answers):\n"
"... print('What is your {0}? It is {1}.'.format(q, a))\n"
"...\n"
"What is your name? It is lancelot.\n"
"What is your quest? It is the holy grail.\n"
"What is your favorite color? It is blue."
msgstr ""
#: ../../tutorial/datastructures.rst:600
msgid ""
"To loop over a sequence in reverse, first specify the sequence in a forward "
"direction and then call the :func:`reversed` function. ::"
msgstr ""
#: ../../tutorial/datastructures.rst:603
msgid ""
">>> for i in reversed(range(1, 10, 2)):\n"
"... print(i)\n"
"...\n"
"9\n"
"7\n"
"5\n"
"3\n"
"1"
msgstr ""
#: ../../tutorial/datastructures.rst:612
msgid ""
"To loop over a sequence in sorted order, use the :func:`sorted` function "
"which returns a new sorted list while leaving the source unaltered. ::"
msgstr ""
#: ../../tutorial/datastructures.rst:615
msgid ""
">>> basket = ['apple', 'orange', 'apple', 'pear', 'orange', 'banana']\n"
">>> for i in sorted(basket):\n"
"... print(i)\n"
"...\n"
"apple\n"
"apple\n"
"banana\n"
"orange\n"
"orange\n"
"pear"
msgstr ""
#: ../../tutorial/datastructures.rst:626
msgid ""
"Using :func:`set` on a sequence eliminates duplicate elements. The use of :"
"func:`sorted` in combination with :func:`set` over a sequence is an "
"idiomatic way to loop over unique elements of the sequence in sorted "
"order. ::"
msgstr ""
#: ../../tutorial/datastructures.rst:630
msgid ""
">>> basket = ['apple', 'orange', 'apple', 'pear', 'orange', 'banana']\n"
">>> for f in sorted(set(basket)):\n"
"... print(f)\n"
"...\n"
"apple\n"
"banana\n"
"orange\n"
"pear"
msgstr ""
#: ../../tutorial/datastructures.rst:639
msgid ""
"It is sometimes tempting to change a list while you are looping over it; "
"however, it is often simpler and safer to create a new list instead. ::"
msgstr ""
#: ../../tutorial/datastructures.rst:642
msgid ""
">>> import math\n"
">>> raw_data = [56.2, float('NaN'), 51.7, 55.3, 52.5, float('NaN'), 47.8]\n"
">>> filtered_data = []\n"
">>> for value in raw_data:\n"
"... if not math.isnan(value):\n"
"... filtered_data.append(value)\n"
"...\n"
">>> filtered_data\n"
"[56.2, 51.7, 55.3, 52.5, 47.8]"
msgstr ""
#: ../../tutorial/datastructures.rst:656
msgid "More on Conditions"
msgstr ""
#: ../../tutorial/datastructures.rst:658
msgid ""
"The conditions used in ``while`` and ``if`` statements can contain any "
"operators, not just comparisons."
msgstr ""
#: ../../tutorial/datastructures.rst:662
msgid ""
"The comparison operators ``in`` and ``not in`` are membership tests that "
"determine whether a value is in (or not in) a container. The operators "
"``is`` and ``is not`` compare whether two objects are really the same "
"object. All comparison operators have the same priority, which is lower "
"than that of all numerical operators."
msgstr ""
#: ../../tutorial/datastructures.rst:668
msgid ""
"Comparisons can be chained. For example, ``a < b == c`` tests whether ``a`` "
"is less than ``b`` and moreover ``b`` equals ``c``."
msgstr ""
#: ../../tutorial/datastructures.rst:671
msgid ""
"Comparisons may be combined using the Boolean operators ``and`` and ``or``, "
"and the outcome of a comparison (or of any other Boolean expression) may be "
"negated with ``not``. These have lower priorities than comparison "
"operators; between them, ``not`` has the highest priority and ``or`` the "
"lowest, so that ``A and not B or C`` is equivalent to ``(A and (not B)) or "
"C``. As always, parentheses can be used to express the desired composition."
msgstr ""
#: ../../tutorial/datastructures.rst:678
msgid ""
"The Boolean operators ``and`` and ``or`` are so-called *short-circuit* "
"operators: their arguments are evaluated from left to right, and evaluation "
"stops as soon as the outcome is determined. For example, if ``A`` and ``C`` "
"are true but ``B`` is false, ``A and B and C`` does not evaluate the "
"expression ``C``. When used as a general value and not as a Boolean, the "
"return value of a short-circuit operator is the last evaluated argument."
msgstr ""
#: ../../tutorial/datastructures.rst:685
msgid ""
"It is possible to assign the result of a comparison or other Boolean "
"expression to a variable. For example, ::"
msgstr ""
#: ../../tutorial/datastructures.rst:688
msgid ""
">>> string1, string2, string3 = '', 'Trondheim', 'Hammer Dance'\n"
">>> non_null = string1 or string2 or string3\n"
">>> non_null\n"
"'Trondheim'"
msgstr ""
#: ../../tutorial/datastructures.rst:693
msgid ""
"Note that in Python, unlike C, assignment inside expressions must be done "
"explicitly with the :ref:`walrus operator <why-can-t-i-use-an-assignment-in-"
"an-expression>` ``:=``. This avoids a common class of problems encountered "
"in C programs: typing ``=`` in an expression when ``==`` was intended."
msgstr ""
#: ../../tutorial/datastructures.rst:703
msgid "Comparing Sequences and Other Types"
msgstr ""
#: ../../tutorial/datastructures.rst:704
msgid ""
"Sequence objects typically may be compared to other objects with the same "
"sequence type. The comparison uses *lexicographical* ordering: first the "
"first two items are compared, and if they differ this determines the outcome "
"of the comparison; if they are equal, the next two items are compared, and "
"so on, until either sequence is exhausted. If two items to be compared are "
"themselves sequences of the same type, the lexicographical comparison is "
"carried out recursively. If all items of two sequences compare equal, the "
"sequences are considered equal. If one sequence is an initial sub-sequence "
"of the other, the shorter sequence is the smaller (lesser) one. "
"Lexicographical ordering for strings uses the Unicode code point number to "
"order individual characters. Some examples of comparisons between sequences "
"of the same type::"
msgstr ""
#: ../../tutorial/datastructures.rst:716
msgid ""
"(1, 2, 3) < (1, 2, 4)\n"
"[1, 2, 3] < [1, 2, 4]\n"
"'ABC' < 'C' < 'Pascal' < 'Python'\n"
"(1, 2, 3, 4) < (1, 2, 4)\n"
"(1, 2) < (1, 2, -1)\n"
"(1, 2, 3) == (1.0, 2.0, 3.0)\n"
"(1, 2, ('aa', 'ab')) < (1, 2, ('abc', 'a'), 4)"
msgstr ""
#: ../../tutorial/datastructures.rst:724
msgid ""
"Note that comparing objects of different types with ``<`` or ``>`` is legal "
"provided that the objects have appropriate comparison methods. For example, "
"mixed numeric types are compared according to their numeric value, so 0 "
"equals 0.0, etc. Otherwise, rather than providing an arbitrary ordering, "
"the interpreter will raise a :exc:`TypeError` exception."
msgstr ""
#: ../../tutorial/datastructures.rst:732
msgid "Footnotes"
msgstr ""
You can’t perform that action at this time.