chargrep.py

#!/usr/bin/env python
#
# Check if a file contains a set of chars
#
import argparse
import logging
import sys
import time
import collections
import unittest
import itertools


def read_file(path):
    if not path:
        return sys.stdin.read()
    else:
        with open(path) as fin:
            return fin.read()


def chargrep_loop(chars, longstr):
    for c in chars:
        if longstr.find(c) != -1:
            return True
    return False


def chargrep_set(chars, longstr):
    return len(chars.intersection(set(longstr))) != 0


def chargrep_counter(chars, longstr):
    counter = collections.Counter(longstr)
    return len(set(chars).intersection(counter.keys())) != 0


def chargrep_itertools(chars, longstr):
    #
    # https://www.safaribooksonline.com/library/view/python-cookbook-2nd/0596007973/ch01s09.html
    #
    for item in itertools.ifilter(chars.__contains__, longstr):
        return True
    return False


class CharGrepTest(unittest.TestCase):

    def sanity_test(self):
        self.assertTrue(chargrep_loop("abc", "the quick brown fox"))
        self.assertFalse(chargrep_loop("yz", "the quick brown fox"))


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("chars", type=str, default=None)
    parser.add_argument("file", nargs="?", type=str, default=None)
    parser.add_argument("-m", "--method", type=str, default="loop")
    parser.add_argument("-l", "--loglevel", type=str, default="ERROR")
    args = parser.parse_args()

    logging.basicConfig(level=args.loglevel)

    the_file = read_file(args.file)

    the_method = globals()["chargrep_" + args.method]
    before = time.time()
    result = the_method(set(args.chars), the_file)
    after = time.time()

    print result
    logging.info("took %.2fs" % (after - before))


if __name__ == "__main__":
    main()