[解決済み] 組込み開関数におけるモードa、a+、w、w+、r+の違い？

質問

Pythonのビルトインで 開く 関数のモードはどうなっていますか？ w , a , w+ , a+ および r+ ?

特に、ドキュメントでは、これらすべてがファイルへの書き込みを可能にすることを暗示し、特に "appending", "writing", "updating" のためにファイルを開くと述べていますが、これらの用語が何を意味するかは定義されていません。

どのように解決するのですか？

オープニングモードはC標準ライブラリ関数と全く同じです fopen() .

BSDの fopen マンページ は、以下のように定義しています。

 The argument mode points to a string beginning with one of the following
 sequences (Additional characters may follow these sequences.):

 ``r''   Open text file for reading.  The stream is positioned at the
         beginning of the file.

 ``r+''  Open for reading and writing.  The stream is positioned at the
         beginning of the file.

 ``w''   Truncate file to zero length or create text file for writing.
         The stream is positioned at the beginning of the file.

 ``w+''  Open for reading and writing.  The file is created if it does not
         exist, otherwise it is truncated.  The stream is positioned at
         the beginning of the file.

 ``a''   Open for writing.  The file is created if it does not exist.  The
         stream is positioned at the end of the file.  Subsequent writes
         to the file will always end up at the then current end of file,
         irrespective of any intervening fseek(3) or similar.

 ``a+''  Open for reading and writing.  The file is created if it does not
         exist.  The stream is positioned at the end of the file.  Subse-
         quent writes to the file will always end up at the then current
         end of file, irrespective of any intervening fseek(3) or similar.