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GeezerVison is showing github.com — python-docs-ja/library/contextlib.po at 3.13 · python/python-docs-ja Expand file tree/ Copy pathcontextlib.poMore file actions 2048 lines (1876 loc) · 83.3 KB / Copy pathcontextlib.poFile metadata and controls2048 lines (1876 loc) · 83.3 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: # Takanori Suzuki <[email protected]>, 2021 # tomo, 2021 # Osamu NAKAMURA, 2021 # Takeshi Nakazato, 2022 # 石井明久, 2024 # #, fuzzy msgid "" msgstr "" "Project-Id-Version: Python 3.14\n" "Report-Msgid-Bugs-To: \n" "POT-Creation-Date: 2025-05-16 14:19+0000\n" "PO-Revision-Date: 2021-06-28 00:57+0000\n" "Last-Translator: 石井明久, 2024\n" "Language-Team: Japanese (https://app.transifex.com/python-doc/teams/5390/" "ja/)\n" "Language: ja\n" "MIME-Version: 1.0\n" "Content-Type: text/plain; charset=UTF-8\n" "Content-Transfer-Encoding: 8bit\n" "Plural-Forms: nplurals=1; plural=0;\n" #: ../../library/contextlib.rst:2 msgid "" ":mod:`!contextlib` --- Utilities for :keyword:`!with`\\ -statement contexts" msgstr ":mod:`!contextlib` --- :keyword:`!with` 文コンテキスト用ユーティリティ" #: ../../library/contextlib.rst:7 msgid "**Source code:** :source:`Lib/contextlib.py`" msgstr "**ソースコード:** :source:`Lib/contextlib.py`" #: ../../library/contextlib.rst:11 msgid "" "This module provides utilities for common tasks involving " "the :keyword:`with` statement. For more information see " "also :ref:`typecontextmanager` and :ref:`context-managers`." msgstr "" "このモジュールは :keyword:`with` 文に関わる一般的なタスクのためのユーティリ" "ティを提供します。詳しい情報は、 :ref:`typecontextmanager` と :ref:`context-" "managers` を参照してください。" #: ../../library/contextlib.rst:17 msgid "Utilities" msgstr "ユーティリティ" #: ../../library/contextlib.rst:19 msgid "Functions and classes provided:" msgstr "以下の関数とクラスを提供しています:" #: ../../library/contextlib.rst:23 msgid "" "An :term:`abstract base class` for classes that " "implement :meth:`object.__enter__` and :meth:`object.__exit__`. A default " "implementation for :meth:`object.__enter__` is provided which returns " "``self`` while :meth:`object.__exit__` is an abstract method which by " "default returns ``None``. See also the definition " "of :ref:`typecontextmanager`." msgstr "" ":meth:`object.__enter__` と :meth:`object.__exit__` の2つのメソッドを実装した" "抽象基底クラス (:term:`abstract base class`) です。 :meth:`object.__enter__` " "は ``self`` を返すデフォルトの実装が提供されるいっぽ" "う、 :meth:`object.__exit__` はデフォルトで ``None`` を返す抽象メソッドで" "す。 :ref:`typecontextmanager` の定義も参照してください。" #: ../../library/contextlib.rst:34 msgid "" "An :term:`abstract base class` for classes that " "implement :meth:`object.__aenter__` and :meth:`object.__aexit__`. A default " "implementation for :meth:`object.__aenter__` is provided which returns " "``self`` while :meth:`object.__aexit__` is an abstract method which by " "default returns ``None``. See also the definition of :ref:`async-context-" "managers`." msgstr "" ":meth:`object.__aenter__` と :meth:`object.__aexit__` の2つのメソッドを実装す" "るクラスのための抽象基底クラス (:term:`abstract base class`) で" "す。 :meth:`object.__aenter__` は ``self`` を返すデフォルト実装が提供される" "いっぽう、 :meth:`object.__aexit__` はデフォルトで ``None`` を返す抽象メソッ" "ドです。 :ref:`async-context-managers` の定義も参照してください。" #: ../../library/contextlib.rst:46 msgid "" "This function is a :term:`decorator` that can be used to define a factory " "function for :keyword:`with` statement context managers, without needing to " "create a class or separate :meth:`~object.__enter__` " "and :meth:`~object.__exit__` methods." msgstr "" "この関数は :keyword:`with` 文コンテキストマネージャのファクトリ関数を定義する" "ために利用できる :term:`デコレータ <decorator>` です。新しいクラス" "や :meth:`~object.__enter__` と :meth:`~object.__exit__` メソッドを別々に定義" "しなくても、ファクトリ関数を定義することができます。" msgid "" "While many objects natively support use in with statements, sometimes a " "resource needs to be managed that isn't a context manager in its own right, " "and doesn't implement a ``close()`` method for use with " "``contextlib.closing``." msgstr "" "多くのオブジェクトは with 文での使用をサポートしていますが、コンテキストマ" "ネージャではなく、``contextlib.closing`` で使うための ``close()`` メソッドも" "実装していないリソースを管理する必要が生じることもあります。" #: ../../library/contextlib.rst:54 msgid "" "An abstract example would be the following to ensure correct resource " "management::" msgstr "" "リソースを正しく管理するよう保証する抽象的な例は以下のようなものでしょう::" msgid "" "from contextlib import contextmanager\n" "\n" "@contextmanager\n" "def managed_resource(*args, **kwds):\n" " # Code to acquire resource, e.g.:\n" " resource = acquire_resource(*args, **kwds)\n" " try:\n" " yield resource\n" " finally:\n" " # Code to release resource, e.g.:\n" " release_resource(resource)" msgstr "" "from contextlib import contextmanager\n" "\n" "@contextmanager\n" "def managed_resource(*args, **kwds):\n" " # リソースを確保するコードの例:\n" " resource = acquire_resource(*args, **kwds)\n" " try:\n" " yield resource\n" " finally:\n" " # リソースを解放するコードの例:\n" " release_resource(resource)" #: ../../library/contextlib.rst:69 msgid "The function can then be used like this::" msgstr "このとき、関数は次のように使うことができます::" msgid "" ">>> with managed_resource(timeout=3600) as resource:\n" "... # Resource is released at the end of this block,\n" "... # even if code in the block raises an exception" msgstr "" ">>> with managed_resource(timeout=3600) as resource:\n" "... # ブロック内のコードが例外を送出しても、\n" "... # ブロックの終わりでリソースは解放されます" #: ../../library/contextlib.rst:75 msgid "" "The function being decorated must return a :term:`generator`-iterator when " "called. This iterator must yield exactly one value, which will be bound to " "the targets in the :keyword:`with` statement's :keyword:`!as` clause, if any." msgstr "" "デコレート対象の関数は呼び出されたときに :term:`ジェネレータ <generator>`-イ" "テレータを返す必要があります。このイテレータは必ず値を1つ yield しなければな" "りません。 :keyword:`with` 文の :keyword:`!as` 節が存在するなら、その値は as " "節のターゲットへ束縛されることになります。" #: ../../library/contextlib.rst:79 msgid "" "At the point where the generator yields, the block nested in " "the :keyword:`with` statement is executed. The generator is then resumed " "after the block is exited. If an unhandled exception occurs in the block, it " "is reraised inside the generator at the point where the yield occurred. " "Thus, you can use a :keyword:`try`...\\ :keyword:`except`..." "\\ :keyword:`finally` statement to trap the error (if any), or ensure that " "some cleanup takes place. If an exception is trapped merely in order to log " "it or to perform some action (rather than to suppress it entirely), the " "generator must reraise that exception. Otherwise the generator context " "manager will indicate to the :keyword:`!with` statement that the exception " "has been handled, and execution will resume with the statement immediately " "following the :keyword:`!with` statement." msgstr "" "ジェネレータが yield を実行した箇所で :keyword:`with` 文のネストされたブロッ" "クが実行されます。ブロックから抜けた後でジェネレータは再開されます。ブロック" "内で処理されない例外が発生した場合は、ジェネレータ内部の yield を実行した箇所" "で例外が再送出されます。なので、(もしあれば) エラーを捕捉したり、クリーンアッ" "プ処理を確実に実行したりするために、:keyword:`try`...\\ :keyword:`except`..." "\\ :keyword:`finally` 構文を使用できます。例外を捕捉する目的が、(完全に例外を" "抑制してしまうのではなく) 単に例外のログをとるため、もしくはあるアクションを" "実行するためなら、ジェネレータはその例外を再送出しなければなりません。例外を" "再送出しない場合、ジェネレータのコンテキストマネージャは :keyword:`!with` 文" "に対して例外が処理されたことを示し、:keyword:`!with` 文の直後の文から実行を再" "開します。" #: ../../library/contextlib.rst:91 msgid "" ":func:`contextmanager` uses :class:`ContextDecorator` so the context " "managers it creates can be used as decorators as well as in :keyword:`with` " "statements. When used as a decorator, a new generator instance is implicitly " "created on each function call (this allows the otherwise \"one-shot\" " "context managers created by :func:`contextmanager` to meet the requirement " "that context managers support multiple invocations in order to be used as " "decorators)." msgstr "" ":func:`contextmanager` は :class:`ContextDecorator` を使っているの" "で、 :func:`contextmanager` で作ったコンテキストマネージャは :keyword:`with` " "文だけでなくデコレータとしても利用できます。デコレーターとして利用された場" "合、新しい generator インスタンスが関数呼び出しのたびに暗黙に生成されます (こ" "のことによって、 :func:`contextmanager` によって作られたなにがしか「単発」コ" "ンテキストマネージャを、コンテキストマネージャがデコレータとして使われるため" "には多重に呼び出されることをサポートする必要がある、という要件に合致させるこ" "とが出来ます。)" #: ../../library/contextlib.rst:98 msgid "Use of :class:`ContextDecorator`." msgstr ":class:`ContextDecorator` の使用。" #: ../../library/contextlib.rst:104 msgid "" "Similar to :func:`~contextlib.contextmanager`, but creates " "an :ref:`asynchronous context manager <async-context-managers>`." msgstr "" ":func:`~contextlib.contextmanager` と似ていますが、 :ref:`非同期コンテキスト" "マネージャ (asynchronous context manager) <async-context-managers>` を生成し" "ます。" #: ../../library/contextlib.rst:107 msgid "" "This function is a :term:`decorator` that can be used to define a factory " "function for :keyword:`async with` statement asynchronous context managers, " "without needing to create a class or separate :meth:`~object.__aenter__` " "and :meth:`~object.__aexit__` methods. It must be applied to " "an :term:`asynchronous generator` function." msgstr "" "この関数は :keyword:`async with` 文のための非同期コンテキストマネージャのファ" "クトリ関数を定義するために利用できるデコレータ (:term:`decorator`) です。新し" "いクラスや :meth:`~object.__aenter__` と :meth:`~object.__aexit__` メソッド" "を個別に定義する必要はありません。このデコレータは非同期ジェネレータ " "(:term:`asynchronous generator`) 関数に適用しなければなりません。" #: ../../library/contextlib.rst:113 msgid "A simple example::" msgstr "簡単な例::" msgid "" "from contextlib import asynccontextmanager\n" "\n" "@asynccontextmanager\n" "async def get_connection():\n" " conn = await acquire_db_connection()\n" " try:\n" " yield conn\n" " finally:\n" " await release_db_connection(conn)\n" "\n" "async def get_all_users():\n" " async with get_connection() as conn:\n" " return conn.query('SELECT ...')" msgstr "" "from contextlib import asynccontextmanager\n" "\n" "@asynccontextmanager\n" "async def get_connection():\n" " conn = await acquire_db_connection()\n" " try:\n" " yield conn\n" " finally:\n" " await release_db_connection(conn)\n" "\n" "async def get_all_users():\n" " async with get_connection() as conn:\n" " return conn.query('SELECT ...')" #: ../../library/contextlib.rst:131 msgid "" "Context managers defined with :func:`asynccontextmanager` can be used either " "as decorators or with :keyword:`async with` statements::" msgstr "" ":func:`asynccontextmanager` とともに定義されたコンテキストマネージャは、デコ" "レータとして使うことも :keyword:`async with` 文と組み合わせて使うこともできま" "す::" msgid "" "import time\n" "from contextlib import asynccontextmanager\n" "\n" "@asynccontextmanager\n" "async def timeit():\n" " now = time.monotonic()\n" " try:\n" " yield\n" " finally:\n" " print(f'it took {time.monotonic() - now}s to run')\n" "\n" "@timeit()\n" "async def main():\n" " # ... async code ..." msgstr "" "import time\n" "from contextlib import asynccontextmanager\n" "\n" "@asynccontextmanager\n" "async def timeit():\n" " now = time.monotonic()\n" " try:\n" " yield\n" " finally:\n" " print(f'it took {time.monotonic() - now}s to run')\n" "\n" "@timeit()\n" "async def main():\n" " # ... 非同期のコード ..." #: ../../library/contextlib.rst:149 msgid "" "When used as a decorator, a new generator instance is implicitly created on " "each function call. This allows the otherwise \"one-shot\" context managers " "created by :func:`asynccontextmanager` to meet the requirement that context " "managers support multiple invocations in order to be used as decorators." msgstr "" "デコレータとして使われた場合は、各関数呼び出しに対して暗黙のうちに新しいジェ" "ネレータインスタンスが生成されます。これにより、 :func:`asynccontextmanager` " "で生成された単回使用のコンテキストマネージャが複数回呼び出し可能となり、コン" "テキストマネージャをデコレータとして使うことができるための要件を満たすように" "することができます。" #: ../../library/contextlib.rst:154 msgid "" "Async context managers created with :func:`asynccontextmanager` can be used " "as decorators." msgstr "" ":func:`asynccontextmanager` により生成された非同期コンテキストマネージャをデ" "コレータとして使うことができるようになりました。" #: ../../library/contextlib.rst:161 msgid "" "Return a context manager that closes *thing* upon completion of the block. " "This is basically equivalent to::" msgstr "" "ブロックの完了時に *thing* を close するコンテキストマネージャを返します。こ" "れは基本的に以下と等価です::" msgid "" "from contextlib import contextmanager\n" "\n" "@contextmanager\n" "def closing(thing):\n" " try:\n" " yield thing\n" " finally:\n" " thing.close()" msgstr "" "from contextlib import contextmanager\n" "\n" "@contextmanager\n" "def closing(thing):\n" " try:\n" " yield thing\n" " finally:\n" " thing.close()" #: ../../library/contextlib.rst:173 msgid "And lets you write code like this::" msgstr "" "そして、明示的に ``page`` を close する必要なしに、次のように書くことができま" "す::" msgid "" "from contextlib import closing\n" "from urllib.request import urlopen\n" "\n" "with closing(urlopen('https://www.python.org')) as page:\n" " for line in page:\n" " print(line)" msgstr "" "from contextlib import closing\n" "from urllib.request import urlopen\n" "\n" "with closing(urlopen('https://www.python.org')) as page:\n" " for line in page:\n" " print(line)" #: ../../library/contextlib.rst:182 msgid "" "without needing to explicitly close ``page``. Even if an error occurs, " "``page.close()`` will be called when the :keyword:`with` block is exited." msgstr "" "``page`` を明示的に close する必要は無く、エラーが発生した場合で" "も、 :keyword:`with` ブロックを出るときに ``page.close()`` が呼ばれます。" msgid "" "Most types managing resources support the :term:`context manager` protocol, " "which closes *thing* on leaving the :keyword:`with` statement. As " "such, :func:`!closing` is most useful for third party types that don't " "support context managers. This example is purely for illustration purposes, " "as :func:`~urllib.request.urlopen` would normally be used in a context " "manager." msgstr "" "リソースを管理するほとんどの型は :term:`context manager` プロトコルをサポート" "し、:keyword:`with` 文を抜けるときに *thing* を閉じます。\n" "そのため、:func:`!closing` はコンテキストマネージャをサポートしないサードパー" "ティー製の型で特に役立ちます。\n" ":func:`~urllib.request.urlopen` は通常、コンテキストマネージャとして使用する" "ため、この例は説明のためのものにすぎません。" #: ../../library/contextlib.rst:196 msgid "" "Return an async context manager that calls the ``aclose()`` method of " "*thing* upon completion of the block. This is basically equivalent to::" msgstr "" "ブロックの完了時に *thing* の ``aclose()`` メソッドを呼び出すような非同期コン" "テキストマネージャを返します。これは基本的に以下と等価です::" msgid "" "from contextlib import asynccontextmanager\n" "\n" "@asynccontextmanager\n" "async def aclosing(thing):\n" " try:\n" " yield thing\n" " finally:\n" " await thing.aclose()" msgstr "" "from contextlib import asynccontextmanager\n" "\n" "@asynccontextmanager\n" "async def aclosing(thing):\n" " try:\n" " yield thing\n" " finally:\n" " await thing.aclose()" #: ../../library/contextlib.rst:208 msgid "" "Significantly, ``aclosing()`` supports deterministic cleanup of async " "generators when they happen to exit early by :keyword:`break` or an " "exception. For example::" msgstr "" "重要なことは、たとえば次の例のように :keyword:`break` や例外によって早期にブ" "ロックが終了した場合に、 ``aclosing()`` は非同期ジェネレータの決定論的なク" "リーンアップをサポートすることです::" msgid "" "from contextlib import aclosing\n" "\n" "async with aclosing(my_generator()) as values:\n" " async for value in values:\n" " if value == 42:\n" " break" msgstr "" "from contextlib import aclosing\n" "\n" "async with aclosing(my_generator()) as values:\n" " async for value in values:\n" " if value == 42:\n" " break" #: ../../library/contextlib.rst:219 msgid "" "This pattern ensures that the generator's async exit code is executed in the " "same context as its iterations (so that exceptions and context variables " "work as expected, and the exit code isn't run after the lifetime of some " "task it depends on)." msgstr "" "このパターンは、ジェネレータの非同期な終了のコードがイテレーション処理と同じ" "コンテキストの中で実行されることを保証します (すなわち例外とコンテキスト変数" "は期待通りに動作し、またジェネレータが依存するタスクの寿命が尽きたあとに終了" "のコードが実行されることもありません)。" #: ../../library/contextlib.rst:231 msgid "" "Return a context manager that returns *enter_result* from ``__enter__``, but " "otherwise does nothing. It is intended to be used as a stand-in for an " "optional context manager, for example::" msgstr "" "*enter_result* を ``__enter__`` メソッドが返すだけで、その他は何もしないコン" "テキストマネージャを返します。たとえば以下のように、ある機能を持った別のコン" "テキストマネージャに対する、選択可能な代役として使われることが意図されていま" "す::" msgid "" "def myfunction(arg, ignore_exceptions=False):\n" " if ignore_exceptions:\n" " # Use suppress to ignore all exceptions.\n" " cm = contextlib.suppress(Exception)\n" " else:\n" " # Do not ignore any exceptions, cm has no effect.\n" " cm = contextlib.nullcontext()\n" " with cm:\n" " # Do something" msgstr "" "def myfunction(arg, ignore_exceptions=False):\n" " if ignore_exceptions:\n" " # suppress を使ってすべての例外を無視します。\n" " cm = contextlib.suppress(Exception)\n" " else:\n" " # 例外を無視せず、cm は何も行いません。\n" " cm = contextlib.nullcontext()\n" " with cm:\n" " # 何らかの処理" #: ../../library/contextlib.rst:245 msgid "An example using *enter_result*::" msgstr "*enter_result* を使った例です::" msgid "" "def process_file(file_or_path):\n" " if isinstance(file_or_path, str):\n" " # If string, open file\n" " cm = open(file_or_path)\n" " else:\n" " # Caller is responsible for closing file\n" " cm = nullcontext(file_or_path)\n" "\n" " with cm as file:\n" " # Perform processing on the file" msgstr "" "def process_file(file_or_path):\n" " if isinstance(file_or_path, str):\n" " # 文字列の場合はファイルを開きます\n" " cm = open(file_or_path)\n" " else:\n" " # ファイルを閉じる責任は呼び出し側にあります\n" " cm = nullcontext(file_or_path)\n" "\n" " with cm as file:\n" " # ファイルを処理します" #: ../../library/contextlib.rst:258 msgid "" "It can also be used as a stand-in for :ref:`asynchronous context managers " "<async-context-managers>`::" msgstr "" ":ref:`非同期コンテキストマネージャ <async-context-managers>` の代役として使う" "こともできます::" msgid "" "async def send_http(session=None):\n" " if not session:\n" " # If no http session, create it with aiohttp\n" " cm = aiohttp.ClientSession()\n" " else:\n" " # Caller is responsible for closing the session\n" " cm = nullcontext(session)\n" "\n" " async with cm as session:\n" " # Send http requests with session" msgstr "" "async def send_http(session=None):\n" " if not session:\n" " # HTTP セッションがなければ aiohttp で作成します\n" " cm = aiohttp.ClientSession()\n" " else:\n" " # セッションを閉じる責任は呼び出し側にあります\n" " cm = nullcontext(session)\n" "\n" " async with cm as session:\n" " # session を使って HTTP リクエストを送信します" #: ../../library/contextlib.rst:274 msgid ":term:`asynchronous context manager` support was added." msgstr "" "非同期コンテキストマネージャ (:term:`asynchronous context manager`) のサポー" "トが追加されました。" #: ../../library/contextlib.rst:281 msgid "" "Return a context manager that suppresses any of the specified exceptions if " "they occur in the body of a :keyword:`!with` statement and then resumes " "execution with the first statement following the end of the :keyword:`!with` " "statement." msgstr "" ":keyword:`!with` 文の内部で指定された例外の発生を抑えるコンテキストマネージャ" "を返します。 :keyword:`!with` 文の後に続く最初の文から処理が再開されます。" #: ../../library/contextlib.rst:286 msgid "" "As with any other mechanism that completely suppresses exceptions, this " "context manager should be used only to cover very specific errors where " "silently continuing with program execution is known to be the right thing to " "do." msgstr "" "ほかの完全に例外を抑制するメカニズム同様、このコンテキストマネージャは、黙っ" "てプログラム実行を続けることが正しいことであるとわかっている、非常に限定的な" "エラーをカバーする以上の使い方はしてはいけません。" #: ../../library/contextlib.rst:291 msgid "For example::" msgstr "例えば::" msgid "" "from contextlib import suppress\n" "\n" "with suppress(FileNotFoundError):\n" " os.remove('somefile.tmp')\n" "\n" "with suppress(FileNotFoundError):\n" " os.remove('someotherfile.tmp')" msgstr "" "from contextlib import suppress\n" "\n" "with suppress(FileNotFoundError):\n" " os.remove('somefile.tmp')\n" "\n" "with suppress(FileNotFoundError):\n" " os.remove('someotherfile.tmp')" #: ../../library/contextlib.rst:301 msgid "This code is equivalent to::" msgstr "これは以下と等価です::" msgid "" "try:\n" " os.remove('somefile.tmp')\n" "except FileNotFoundError:\n" " pass\n" "\n" "try:\n" " os.remove('someotherfile.tmp')\n" "except FileNotFoundError:\n" " pass" msgstr "" "try:\n" " os.remove('somefile.tmp')\n" "except FileNotFoundError:\n" " pass\n" "\n" "try:\n" " os.remove('someotherfile.tmp')\n" "except FileNotFoundError:\n" " pass" #: ../../library/contextlib.rst:313 ../../library/contextlib.rst:362 #: ../../library/contextlib.rst:372 ../../library/contextlib.rst:389 msgid "This context manager is :ref:`reentrant <reentrant-cms>`." msgstr "" "このコンテキストマネージャは :ref:`再入可能(リエントラント) <reentrant-cms>` " "です。" msgid "" "If the code within the :keyword:`!with` block raises " "a :exc:`BaseExceptionGroup`, suppressed exceptions are removed from the " "group. Any exceptions of the group which are not suppressed are re-raised " "in a new group which is created using the original " "group's :meth:`~BaseExceptionGroup.derive` method." msgstr "" ":keyword:`!with` ブロック内のコードが :exc:`BaseExceptionGroup` を送出した場" "合、抑制対象の例外はグループから取り除かれます。\n" "グループ内の抑制されなかった例外は、元のグループ" "の :meth:`~BaseExceptionGroup.derive` メソッドで作成した新しいグループにまと" "めて再送出されます。" msgid "" "``suppress`` now supports suppressing exceptions raised as part of " "a :exc:`BaseExceptionGroup`." msgstr "" "``suppress`` は、:exc:`BaseExceptionGroup` の一部として送出された例外の抑制を" "サポートするようになりました。" #: ../../library/contextlib.rst:329 msgid "" "Context manager for temporarily redirecting :data:`sys.stdout` to another " "file or file-like object." msgstr "" ":data:`sys.stdout` を一時的に別のファイルまたは file-like オブジェクトにリダ" "イレクトするコンテキストマネージャです。" #: ../../library/contextlib.rst:332 msgid "" "This tool adds flexibility to existing functions or classes whose output is " "hardwired to stdout." msgstr "" "このツールは、出力先が標準出力 (stdout) に固定されている既存の関数やクラスに" "出力先の柔軟性を追加します。" #: ../../library/contextlib.rst:335 msgid "" "For example, the output of :func:`help` normally is sent to *sys.stdout*. " "You can capture that output in a string by redirecting the output to " "an :class:`io.StringIO` object. The replacement stream is returned from the " "``__enter__`` method and so is available as the target of " "the :keyword:`with` statement::" msgstr "" "たとえば、 :func:`help` の出力は通常標準出力 (*sys.stdout*) に送られます。出" "力される文字列を :class:`io.StringIO` オブジェクトにリダイレクトすることに" "よって捕捉することができます。代替の出力ストリームは ``__enter__`` メソッドに" "よって返されるので、 :keyword:`with` 文のターゲットとして利用可能です::" msgid "" "with redirect_stdout(io.StringIO()) as f:\n" " help(pow)\n" "s = f.getvalue()" msgstr "" "with redirect_stdout(io.StringIO()) as f:\n" " help(pow)\n" "s = f.getvalue()" #: ../../library/contextlib.rst:345 msgid "" "To send the output of :func:`help` to a file on disk, redirect the output to " "a regular file::" msgstr "" ":func:`help` の出力をディスク上のファイルに送るためには、出力を通常のファイル" "にリダイレクトします::" msgid "" "with open('help.txt', 'w') as f:\n" " with redirect_stdout(f):\n" " help(pow)" msgstr "" "with open('help.txt', 'w') as f:\n" " with redirect_stdout(f):\n" " help(pow)" #: ../../library/contextlib.rst:352 msgid "To send the output of :func:`help` to *sys.stderr*::" msgstr "" ":func:`help` の出力を標準エラー出力 (*sys.stderr*) に送るには以下のようにしま" "す::" msgid "" "with redirect_stdout(sys.stderr):\n" " help(pow)" msgstr "" "with redirect_stdout(sys.stderr):\n" " help(pow)" #: ../../library/contextlib.rst:357 msgid "" "Note that the global side effect on :data:`sys.stdout` means that this " "context manager is not suitable for use in library code and most threaded " "applications. It also has no effect on the output of subprocesses. However, " "it is still a useful approach for many utility scripts." msgstr "" ":data:`sys.stdout` のシステム全体にわたる副作用により、このコンテキストマネー" "ジャはライブラリコードやマルチスレッドアプリケーションでの使用には適していま" "せん。また、サブプロセスの出力に対しても効果がありません。そのような制限はあ" "りますが、それでも多くのユーティリティスクリプトに対して有用なアプローチで" "す。" #: ../../library/contextlib.rst:369 msgid "" "Similar to :func:`~contextlib.redirect_stdout` but " "redirecting :data:`sys.stderr` to another file or file-like object." msgstr "" ":func:`~contextlib.redirect_stdout` と同じですが、標準エラー出力 " "(:data:`sys.stderr`) を別のファイルや file-like オブジェクトにリダイレクトし" "ます。" #: ../../library/contextlib.rst:379 msgid "" "Non parallel-safe context manager to change the current working directory. " "As this changes a global state, the working directory, it is not suitable " "for use in most threaded or async contexts. It is also not suitable for most " "non-linear code execution, like generators, where the program execution is " "temporarily relinquished -- unless explicitly desired, you should not yield " "when this context manager is active." msgstr "" "現在の作業ディレクトリを変更するパラレル非安全なコンテキストマネージャです。" "グローバルな状態である作業ディレクトリを変更するため、ほとんどのマルチスレッ" "ドまたは非同期のコンテキストに対する利用は適切ではありません。また、プログラ" "ムの実行権限を一時的に放棄するジェネレータのような、直線的でないコードを実行" "する場合も適切ではありません -- 明確に必要でないかぎり、このコンテキストマ" "ネージャがアクティブな状態で yield すべきではありません。" #: ../../library/contextlib.rst:386 msgid "" "This is a simple wrapper around :func:`~os.chdir`, it changes the current " "working directory upon entering and restores the old one on exit." msgstr "" "これは :func:`~os.chdir` の単純なラッパーで、コンテキストに入るときに現在の作" "業ディレクトリを変更し、終了時に元の作業ディレクトリを復元します。" #: ../../library/contextlib.rst:396 msgid "" "A base class that enables a context manager to also be used as a decorator." msgstr "" "コンテキストマネージャをデコレータとしても使用できるようにする基底クラスで" "す。" #: ../../library/contextlib.rst:398 msgid "" "Context managers inheriting from ``ContextDecorator`` have to implement " "``__enter__`` and ``__exit__`` as normal. ``__exit__`` retains its optional " "exception handling even when used as a decorator." msgstr "" "``ContextDecorator`` から継承したコンテキストマネージャは、通常のコンテキスト" "マネージャーと同じく ``__enter__`` および ``__exit__`` を実装する必要がありま" "す。``__exit__`` はデコレータとして使用された場合でも例外をオプションの引数と" "して受け取ります。" #: ../../library/contextlib.rst:402 msgid "" "``ContextDecorator`` is used by :func:`contextmanager`, so you get this " "functionality automatically." msgstr "" ":func:`contextmanager` は ``ContextDecorator`` を利用しているので、自動的にデ" "コレーターとしても利用できるようになります。" #: ../../library/contextlib.rst:405 msgid "Example of ``ContextDecorator``::" msgstr "``ContextDecorator`` の例::" msgid "" "from contextlib import ContextDecorator\n" "\n" "class mycontext(ContextDecorator):\n" " def __enter__(self):\n" " print('Starting')\n" " return self\n" "\n" " def __exit__(self, *exc):\n" " print('Finishing')\n" " return False" msgstr "" "from contextlib import ContextDecorator\n" "\n" "class mycontext(ContextDecorator):\n" " def __enter__(self):\n" " print('Starting')\n" " return self\n" "\n" " def __exit__(self, *exc):\n" " print('Finishing')\n" " return False" #: ../../library/contextlib.rst:418 ../../library/contextlib.rst:490 msgid "The class can then be used like this::" msgstr "このとき、クラスは次のように使うことができます::" msgid "" ">>> @mycontext()\n" "... def function():\n" "... print('The bit in the middle')\n" "...\n" ">>> function()\n" "Starting\n" "The bit in the middle\n" "Finishing\n" "\n" ">>> with mycontext():\n" "... print('The bit in the middle')\n" "...\n" "Starting\n" "The bit in the middle\n" "Finishing" msgstr "" ">>> @mycontext()\n" "... def function():\n" "... print('The bit in the middle')\n" "...\n" ">>> function()\n" "Starting\n" "The bit in the middle\n" "Finishing\n" "\n" ">>> with mycontext():\n" "... print('The bit in the middle')\n" "...\n" "Starting\n" "The bit in the middle\n" "Finishing" #: ../../library/contextlib.rst:436 msgid "" "This change is just syntactic sugar for any construct of the following form::" msgstr "これは次のような形のコードに対するシンタックスシュガーになります::" msgid "" "def f():\n" " with cm():\n" " # Do stuff" msgstr "" "def f():\n" " with cm():\n" " # 処理を行います" #: ../../library/contextlib.rst:442 msgid "``ContextDecorator`` lets you instead write::" msgstr "``ContextDecorator`` を使うと代わりに次のように書けます::" msgid "" "@cm()\n" "def f():\n" " # Do stuff" msgstr "" "@cm()\n" "def f():\n" " # 処理を行います" #: ../../library/contextlib.rst:448 msgid "" "It makes it clear that the ``cm`` applies to the whole function, rather than " "just a piece of it (and saving an indentation level is nice, too)." msgstr "" "デコレーターを使うと、``cm`` が関数の一部ではなく全体に適用されていることが明" "確になります (インデントレベルを1つ節約できるのもメリットです)。" #: ../../library/contextlib.rst:451 msgid "" "Existing context managers that already have a base class can be extended by " "using ``ContextDecorator`` as a mixin class::" msgstr "" "すでに基底クラスを持っているコンテキストマネージャーも、``ContextDecorator`` " "を mixin クラスとして利用することで拡張できます::" msgid "" "from contextlib import ContextDecorator\n" "\n" "class mycontext(ContextBaseClass, ContextDecorator):\n" " def __enter__(self):\n" " return self\n" "\n" " def __exit__(self, *exc):\n" " return False" msgstr "" "from contextlib import ContextDecorator\n" "\n" "class mycontext(ContextBaseClass, ContextDecorator):\n" " def __enter__(self):\n" " return self\n" "\n" " def __exit__(self, *exc):\n" " return False" #: ../../library/contextlib.rst:464 msgid "" "As the decorated function must be able to be called multiple times, the " "underlying context manager must support use in multiple :keyword:`with` " "statements. If this is not the case, then the original construct with the " "explicit :keyword:`!with` statement inside the function should be used." msgstr "" "デコレートされた関数が複数回呼び出せるように、内部のコンテキストマネージャー" "は複数の :keyword:`with` 文に対応する必要があります。そうでないなら、明示的" "な :keyword:`!with` 文を関数内で利用するべきです。" #: ../../library/contextlib.rst:474 msgid "" "Similar to :class:`ContextDecorator` but only for asynchronous functions." msgstr ":class:`ContextDecorator` と同じですが、非同期関数専用のクラスです。" #: ../../library/contextlib.rst:476 msgid "Example of ``AsyncContextDecorator``::" msgstr "``AsyncContextDecorator`` の使用例::" msgid "" "from asyncio import run\n" "from contextlib import AsyncContextDecorator\n" "\n" "class mycontext(AsyncContextDecorator):\n" " async def __aenter__(self):\n" " print('Starting')\n" " return self\n" "\n" " async def __aexit__(self, *exc):\n" " print('Finishing')\n" " return False" msgstr "" "from asyncio import run\n" "from contextlib import AsyncContextDecorator\n" "\n" "class mycontext(AsyncContextDecorator):\n" " async def __aenter__(self):\n" " print('Starting')\n" " return self\n" "\n" " async def __aexit__(self, *exc):\n" " print('Finishing')\n" " return False" msgid "" ">>> @mycontext()\n" "... async def function():\n" "... print('The bit in the middle')\n" "...\n" ">>> run(function())\n" "Starting\n" "The bit in the middle\n" "Finishing\n" "\n" ">>> async def function():\n" "... async with mycontext():\n" "... print('The bit in the middle')\n" "...\n" ">>> run(function())\n" "Starting\n" "The bit in the middle\n" "Finishing" msgstr "" ">>> @mycontext()\n" "... async def function():\n" "... print('The bit in the middle')\n" "...\n" ">>> run(function())\n" "Starting\n" "The bit in the middle\n" "Finishing\n" "\n" ">>> async def function():\n" "... async with mycontext():\n" "... print('The bit in the middle')\n" "...\n" ">>> run(function())\n" "Starting\n" |
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