用于输出的fileinput.input（）的Python模拟是什么？

Question

fileinput.input() allows to simply loop over all lines in either a list of input files provided via sys.argv[1:] or sys.stdin if the former is empty.

Is there a similarly simple way to output to the last argument if given and sys.stdout otherwise?

Answer 1

You can use the argparse module and add a commandline argument like this:

parser.add_argument('outfile', nargs='?', type=argparse.FileType('w'),
                    default=sys.stdout)

Answer 2

You can check if the final argument is a file, in which case it is an input so set the output to sys.stdout , otherwise open a new file with that name as output and remove it from sys.argv .

Alternatively just use sys.stdout and let your users use > filename to store to a file.