Python equivalent of Perl's while (<>) {…}?
Question
I write a lot of little scripts that process files on a line-by-line basis. In Perl, I use
while (<>) {
do stuff;
}
This is handy because it doesn't care where the input comes from (a file or stdin).
In Python I use this
if len(sys.argv) == 2: # there's a command line argument
sys.stdin = file(sys.argv[1])
for line in sys.stdin.readlines():
do stuff
which doesn't seem very elegant. Is there a Python idiom that easily handles file/stdin input?
Solution
The fileinput module in the standard library is just what you want:
import fileinput
for line in fileinput.input(): ...
OTHER TIPS
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.
fileinput defaults to stdin, so would make it slightly more concise.
If you do a lot of command-line stuff, though, this piping hack is very neat.
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