How do I use the < > commands in my program?

Question

I have written a program that calculates the counts of each word in an input file. At the moment I am getting the filename using sys.argv[1], but I am actually supposed to be using

python word_counts.py < homer.txt > homer.test

I think homer.txt is the input file that is directed to my python script, while homer.test is the file that the output of my script is written to.

How do I make these work in my program?

http://stackoverflow.com/questions/1450393/how-do-you-read-from-stdin-in-python — Havenard, Dec 31 '13 at 00:30

score 3 · Answer 1 · answered Dec 31 '13 at 00:30

The information in homer.txt is provided on standard-in. In python, that is a file handle called sys.stdin:

import sys
for line in sys.stdin: # reads from homer.txt
    # process line
    print(output) # writes to homer.test

homer.test is collecting data from standard-out. In python, the print statement writes to stdout by default. If you want to treat it explicitly as a file handle, you can use sys.stdout.

score 3 · Answer 2 · answered Dec 31 '13 at 00:31

3

Use sys.stdin to read from homer.txt and sys.stdout (or print) to write to homer.test.

answered Dec 31 '13 at 00:31

Andrew Clark

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How do I use the < > commands in my program?

2 Answers2