Performance comparisson of different options to check existence of forbidden symbols in incoming strings (standard 'char in string' vs. RegExp).

check_forbidden.py

#!/usr/bin/env python
#-*- coding: utf-8 -*-
u"""
Created on May 15, 2013

@author: pablito56

@license: MIT

@contact: [email protected]

Performance comparisson of different options to check existence of forbidden
symbols in incoming strings (standard  'char in string' vs. RegExp).

It checks 1, 3, 5 or 8 forbidden characters existence in 1k, 10k or 100k words
of 15, 20 or 30 random characters length.

It tests worst case; forbidden chars are never found.

Results at the end of the file
"""
from string import ascii_letters, punctuation, digits
from random import seed, choice
import timeit
import re


# We check worse case; symbols will never be found
chars = ascii_letters + digits  # + punctuation


seed()


forbidden_8 = (":", "/", "?", "#", "~", "=", "&", "!")
forbidden_1 = forbidden_8[0]
forbidden_1_re = re.compile(forbidden_1)


def check_forbidden():
    num_times = 1000
    symbols_amount = (3, 5, 8)
    words_amount = (1000, 10000, 100000)
    wrods_sizes = (15, 20, 30)
    header = "\t| {:^10} | {:^10} | {:^10} | {:^10} |".format("# SYMBOLS", "TIME NO RE", "TIME RE", "RE SpeedUp")
    log_trace = "\t| {:^10} | {:^10.5f} | {:^10.5f} | {:^10.5f} |"

    for num_words in words_amount:
        for size in wrods_sizes:
            print "CHECKING {} WORDS OF {} CHARS LENGTH:".format(num_words, size)
            words = ["".join([choice(chars) for i in xrange(size)]) for j in xrange(num_words)]

            print header

            def find_forbidden_1():
                return map(lambda w: forbidden_1 in w, words)

            def find_forbidden_1_re():
                return map(lambda w: forbidden_1_re.search(w) is not None, words)

            t_std = timeit.timeit(find_forbidden_1, number=num_times)
            t_res = timeit.timeit(find_forbidden_1_re, number=num_times)
            print log_trace.format(1, t_std, t_res, t_std / t_res)

            for num_symbols in symbols_amount:
                forbidden = forbidden_8[:num_symbols]
                forbidden_re = re.compile("[" + "".join(forbidden) + "]")

                def find_forbidden_N():
                    return map(lambda w: any((f in w for f in forbidden)), words)
#                     return map(lambda w: any((f == c for f in forbidden for c in w)), words)  # Several times slower

                def find_forbidden_N_re():
                    return map(lambda w: forbidden_re.search(w) is not None, words)

                t_std = timeit.timeit(find_forbidden_N, number=num_times)
                t_res = timeit.timeit(find_forbidden_N_re, number=num_times)
                print log_trace.format(num_symbols, t_std, t_res, t_std / t_res)
            print


if __name__ == '__main__':
    check_forbidden()


u"""
Results on MacBook Pro 13" 2.4 Ghz Intel Core i5 8Gb

CHECKING 1000 WORDS OF 15 CHARS LENGTH:
    | # SYMBOLS  | TIME NO RE |  TIME RE   | RE SpeedUp |
    |     1      |  0.22396   |  0.51894   |  0.43157   |
    |     3      |  1.23259   |  0.66840   |  1.84410   |
    |     5      |  1.91099   |  0.69866   |  2.73521   |
    |     8      |  2.21286   |  0.73737   |  3.00100   |

CHECKING 1000 WORDS OF 20 CHARS LENGTH:
    | # SYMBOLS  | TIME NO RE |  TIME RE   | RE SpeedUp |
    |     1      |  0.24142   |  0.56059   |  0.43064   |
    |     3      |  1.35343   |  0.80293   |  1.68561   |
    |     5      |  1.55931   |  0.69956   |  2.22900   |
    |     8      |  2.27682   |  0.70398   |  3.23423   |

CHECKING 1000 WORDS OF 30 CHARS LENGTH:
    | # SYMBOLS  | TIME NO RE |  TIME RE   | RE SpeedUp |
    |     1      |  0.25355   |  0.56270   |  0.45060   |
    |     3      |  1.21860   |  0.78617   |  1.55003   |
    |     5      |  1.54455   |  0.78203   |  1.97506   |
    |     8      |  2.04291   |  1.13801   |  1.79516   |

CHECKING 10000 WORDS OF 15 CHARS LENGTH:
    | # SYMBOLS  | TIME NO RE |  TIME RE   | RE SpeedUp |
    |     1      |  2.33030   |  5.25763   |  0.44322   |
    |     3      |  12.56244  |  6.80868   |  1.84506   |
    |     5      |  15.09999  |  6.68055   |  2.26029   |
    |     8      |  19.07921  |  7.10648   |  2.68476   |

CHECKING 10000 WORDS OF 20 CHARS LENGTH:
    | # SYMBOLS  | TIME NO RE |  TIME RE   | RE SpeedUp |
    |     1      |  2.36260   |  5.80443   |  0.40703   |
    |     3      |  12.29937  |  7.57868   |  1.62289   |
    |     5      |  15.11851  |  7.56908   |  1.99740   |
    |     8      |  19.59392  |  7.70403   |  2.54333   |

CHECKING 10000 WORDS OF 30 CHARS LENGTH:
    | # SYMBOLS  | TIME NO RE |  TIME RE   | RE SpeedUp |
    |     1      |  2.47049   |  5.85040   |  0.42228   |
    |     3      |  12.75136  |  8.43134   |  1.51238   |
    |     5      |  15.77369  |  8.77852   |  1.79685   |
    |     8      |  20.65556  |  8.53470   |  2.42019   |

CHECKING 100000 WORDS OF 15 CHARS LENGTH:
    | # SYMBOLS  | TIME NO RE |  TIME RE   | RE SpeedUp |
    |     1      |  24.20128  |  55.73680  |  0.43421   |
    |     3      | 122.62828  |  69.88992  |  1.75459   |
    |     5      | 148.97942  |  68.43717  |  2.17688   |
    |     8      | 188.52356  |  69.15813  |  2.72598   |

CHECKING 100000 WORDS OF 20 CHARS LENGTH:
    | # SYMBOLS  | TIME NO RE |  TIME RE   | RE SpeedUp |
    |     1      |  24.71635  |  55.20613  |  0.44771   |
    |     3      | 122.12375  |  73.54637  |  1.66050   |
    |     5      | 150.11232  |  72.87738  |  2.05979   |
    |     8      | 191.79193  |  73.47913  |  2.61016   |

CHECKING 100000 WORDS OF 30 CHARS LENGTH:
    | # SYMBOLS  | TIME NO RE |  TIME RE   | RE SpeedUp |
    |     1      |  25.36807  |  56.23131  |  0.45114   |
    |     3      | 125.01627  |  82.79500  |  1.50995   |
    |     5      | 155.50607  |  82.55599  |  1.88364   |
    |     8      | 204.95154  |  84.17276  |  2.43489   |
"""