fileinput --- 逐列疊代多個輸入串流

原始碼：Lib/fileinput.py

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This module implements a helper class and functions to quickly write a loop over standard input or a list of files. If you just want to read or write one file see open().

The typical use is:

import fileinput
for line in fileinput.input(encoding="utf-8"):
    process(line)

This iterates over the lines of all files listed in sys.argv[1:], defaulting to sys.stdin if the list is empty. If a filename is '-', it is also replaced by sys.stdin and the optional arguments mode and openhook are ignored. To specify an alternative list of filenames, pass it as the first argument to input(). A single file name is also allowed.

All files are opened in text mode by default, but you can override this by specifying the mode parameter in the call to input() or FileInput. If an I/O error occurs during opening or reading a file, OSError is raised.

在 3.3 版的變更: IOError 曾經被引發；現在它是一個 OSError 的別名。

If sys.stdin is used more than once, the second and further use will return no lines, except perhaps for interactive use, or if it has been explicitly reset (e.g. using sys.stdin.seek(0)).

Empty files are opened and immediately closed; the only time their presence in the list of filenames is noticeable at all is when the last file opened is empty.

Lines are returned with any newlines intact, which means that the last line in a file may not have one.

You can control how files are opened by providing an opening hook via the openhook parameter to fileinput.input() or FileInput(). The hook must be a function that takes two arguments, filename and mode, and returns an accordingly opened file-like object. If encoding and/or errors are specified, they will be passed to the hook as additional keyword arguments. This module provides a hook_compressed() to support compressed files.

The following function is the primary interface of this module:

fileinput.