word_count.py

#!/usr/bin/env python
# -*- encoding: utf-8 -*-
"""Returns a human-friendly word count of the string passed to stdin.

Example outputs:
* 5 words
* 100 words
* 1.5k words
* 10k words

"""

import subprocess
import sys


def count_words(string):
    """Count the number of words in a string."""
    proc = subprocess.Popen(['wc', '-w'],
                            stdout=subprocess.PIPE,
                            stdin=subprocess.PIPE,
                            stderr=subprocess.STDOUT)
    stdout, _ = proc.communicate(input=string)
    return int(stdout.decode())


def summarise_count(count):
    """Turn a number into a human-friendly word count."""
    assert count >= 0
    if count == 1:
        return '1 word'
    elif count < 1000:
        return '%d words' % count
    else:
        prefix = str(round(count / 1000, ndigits=1))
        if prefix.endswith('.0'):
            return '%dk words' % int(prefix[:-2])
        else:
            return '%sk words' % prefix


if __name__ == '__main__':
    sys.stdout.write(summarise_count(count_words(sys.stdin.read())))