Python - Reading and Writing Files - copy, with文, open関数

Practical Programming
楽天ブックス 紀伊国屋書店

開発環境

• macOS Catalina - Apple (OS)
• Emacs (Text Editor)
• Windows 10 Pro (OS)
• Visual Studio Code (Text Editor)
• Python 3.7 (プログラミング言語)

Practical Programming: An Introduction to Computer Science Using Python 3.6 (Paul Gries(著)、Jennifer Campbell(著)、Jason Montojo(著)、Pragmatic Bookshelf)のChapter 10(Reading and Writing Files)、Exercise 1の解答を求めてみる。

コード

#!/usr/bin/env python3

filename = input('ファイル名: ')
with open(filename) as in_file, open(f'{filename}.bak', 'w') as out_file:
    for line in in_file:
        print(line, file=out_file, end='')

入出力結果(Zsh、PowerShell、Terminal、Jupyter(IPython))

% ./sample1.py
ファイル名: sample1.py
% diff sample1.py sample1.py.bak 
% cat sample1.py.bak 
#!/usr/bin/env python3

filename = input('ファイル名: ')
with open(filename) as in_file, open(f'{filename}.bak', 'w') as out_file:
    for line in in_file:
        print(line, file=out_file, end='')
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