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This module implements a helper class and functions to quickly write aloop over standard input or a list of files.
The typical use is:
import fileinputfor line in fileinput.input(): process(line)
This iterates over the lines of all files listed insys.argv[1:], defaulting tosys.stdin if the list isempty. If a filename is'-', it is also replaced bysys.stdin. To specify an alternative list of filenames, passit as the first argument toinput(). A single file name isalso allowed.
All files are opened in text mode by default, but you can override this byspecifying themode parameter in the call toinput()orFileInput(). If an I/O error occurs during opening or readinga file,IOError is raised.
Ifsys.stdin is used more than once, the second and further usewill return no lines, except perhaps for interactive use, or if it hasbeen explicitly reset (e.g. usingsys.stdin.seek(0)).
Empty files are opened and immediately closed; the only time theirpresence in the list of filenames is noticeable at all is when thelast file opened is empty.
It is possible that the last line of a file does not end in a newlinecharacter; lines are returned including the trailing newline when itis present.
You can control how files are opened by providing an opening hook via theopenhook parameter toinput() orFileInput().The hook must be a function that takes two arguments,filenameandmode, and returns an accordingly opened file-like object.Two useful hooks are already provided by this module.
The following function is the primary interface of this module:
| [files[, inplace[, backup[, mode[, openhook]]]]]) |
Changed in version 2.5:Added themode andopenhook parameters.
The following functions use the global state created byinput(); if there is no active state,RuntimeError is raised.
| ) |
None.| ) |
-1.New in version 2.5.| ) |
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.| ) |
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The class which implements the sequence behavior provided by themodule is available for subclassing as well:
| [files[, inplace[, backup[, mode[, openhook]]]]]) |
Withmode you can specify which file mode will be passed toopen(). It must be one of'r','rU','U' and'rb'.
Theopenhook, when given, must be a function that takes two arguments,filename andmode, and returns an accordingly opened file-like object. You cannot useinplace andopenhook together.
Changed in version 2.5:Added themode andopenhook parameters.
Optional in-place filtering: if the keyword argumentinplace=1 is passed toinput() or to theFileInput constructor, the file is moved to a backup file andstandard output is directed to the input file (if a file of the samename as the backup file already exists, it will be replaced silently).This makes it possible to write a filter that rewrites its input filein place. If the keyword argumentbackup='.<someextension>' is also given, it specifies the extension for the backupfile, and the backup file remains around; by default, the extension is'.bak' and it is deleted when the output file is closed. In-placefiltering is disabled when standard input is read.
Caveat: The current implementation does not work for MS-DOS8+3 filesystems.
The two following opening hooks are provided by this module:
| filename, mode) |
'.gz' and'.bz2') using thegzip andbz2 modules. If the filename extension is not'.gz' or'.bz2', the file is opened normally (ie, usingopen() without any decompression).Usage example: "fi = fileinput.FileInput(openhook=fileinput.hook_compressed)"
New in version 2.5.
| encoding) |
Usage example: "fi = fileinput.FileInput(openhook=fileinput.hook_encoded("iso-8859-1"))"
Note:With this hook,FileInput might return Unicode strings depending on the specifiedencoding.New in version 2.5.
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