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| -rw-r--r-- | Doc/library/functions.rst | 31 |
1 files changed, 16 insertions, 15 deletions
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst index d9d7874..8c0a6ce 100644 --- a/Doc/library/functions.rst +++ b/Doc/library/functions.rst @@ -676,38 +676,39 @@ are always available. They are listed here in alphabetical order. *closefd* is set to ``False``.) *mode* is an optional string that specifies the mode in which the file is - opened. It defaults to ``'r'`` which means open for reading in text mode. - Other common values are ``'w'`` for writing (truncating the file if it - already exists), and ``'a'`` for appending (which on *some* Unix systems, - means that *all* writes append to the end of the file regardless of the - current seek position). In text mode, if *encoding* is not specified the - encoding used is platform dependent. (For reading and writing raw bytes use - binary mode and leave *encoding* unspecified.) The available modes are: + opened. The available modes are: ========= =============================================================== Character Meaning --------- --------------------------------------------------------------- ``'r'`` open for reading (default) - ``'w'`` open for writing, truncating the file first + ``'w'`` open for writing, truncating the file first if it exists ``'a'`` open for writing, appending to the end of the file if it exists - ``'b'`` binary mode + ========= =============================================================== + + Several characters can be appended that modify the given mode: + + ========= =============================================================== ``'t'`` text mode (default) - ``'+'`` open a disk file for updating (reading and writing) + ``'b'`` binary mode + ``'+'`` open for updating (reading and writing) ``'U'`` universal newline mode (for backwards compatibility; should not be used in new code) ========= =============================================================== - The default mode is ``'rt'`` (open for reading text). For binary random - access, the mode ``'w+b'`` opens and truncates the file to 0 bytes, while - ``'r+b'`` opens the file without truncation. + The mode ``'w+'`` opens and truncates the file to 0 bytes, while ``'r+'`` + opens the file without truncation. On *some* Unix systems, append mode means + that *all* writes append to the end of the file regardless of the current + seek position. Python distinguishes between files opened in binary and text modes, even when the underlying operating system doesn't. Files opened in binary mode (including ``'b'`` in the *mode* argument) return contents as ``bytes`` objects without any decoding. In text mode (the default, or when ``'t'`` is included in the *mode* argument), the contents of the file are returned as - strings, the bytes having been first decoded using a platform-dependent - encoding or using the specified *encoding* if given. + strings, the bytes having been first decoded using the specified *encoding*. + If *encoding* is not specified, a platform-dependent default encoding is + used, see below. *buffering* is an optional integer used to set the buffering policy. By default full buffering is on. Pass 0 to switch buffering off (only allowed |