This module implements a helper class and functions to quickly write a loop over standard input or a list of files.
The typical use is:
import fileinput for line in fileinput.input(): 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. To specify an alternative list of filenames, pass
it as the first argument to input(). A single file name is
All files are opened in text mode. If an I/O error occurs during opening or reading a file, IOError is raised.
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
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.
It is possible that the last line of a file does not end in a newline character; lines are returned including the trailing newline when it is present.
The following function is the primary interface of this module:
The following functions use the global state created by input(); if there is no active state, RuntimeError is raised.
0. After the last line of the last file has been read, returns the line number of that line.
0. After the last line of the last file has been read, returns the line number of that line within the file.
sys.stdin, otherwise returns false.
The class which implements the sequence behavior provided by the module is available for subclassing as well:
Optional in-place filtering: if the keyword argument
inplace=1 is passed to input() or to the
FileInput constructor, the file is moved to a backup file and
standard output is directed to the input file.
This makes it possible to write a filter that rewrites its input file
in place. If the keyword argument
extension>' is also given, it specifies the extension for the backup
file, and the backup file remains around; by default, the extension is
'.bak' and it is deleted when the output file is closed. In-place
filtering is disabled when standard input is read.
Caveat: The current implementation does not work for MS-DOS 8+3 filesystems.