mirror of
https://github.com/creyD/entro.py.git
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88 lines
2.9 KiB
Python
88 lines
2.9 KiB
Python
'''
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calc_entro.py calculates the entropy of a given string or file
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This uses the negative sum of the log (to the base of 2) of the probability
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times the probability of a char to occur in a certain string as the entropy.
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'''
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import math
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import argparse
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# Calculates the entropy of a given string (as described in the docstring)
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def calcEntropy(string):
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alphabet, alphabet_size, entropy = {}, 0, 0
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for char in string:
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if char in alphabet:
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alphabet[char] += 1
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else:
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alphabet[char] = 1
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alphabet_size += 1
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for char in alphabet:
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alphabet[char] = alphabet[char] / alphabet_size
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entropy += alphabet[char] * math.log(alphabet[char], 2)
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return -entropy, alphabet
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# Outputs a given entropy including the original text and the alphabet with probabilities
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def printEntropy(original, entropy, alphabet, simple):
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print('---')
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if simple == False:
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print('Content: ' + original)
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print('Probabilities: ' + str(alphabet))
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print('Entropy: ' + str(entropy) + ' bits')
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print('---')
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# Reads a file by a given path
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def getFile(path):
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f = open(path, 'r')
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content = f.read().replace('\n', ' ')
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f.close()
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return content.strip()
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# List of the arguments one can use to influence the behavior of the program
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parser = argparse.ArgumentParser(description='Calculate the information entropy of some strings.')
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# INPUT ARGUMENTS
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parser.add_argument('strings', nargs='*', default='', type=str, help='Strings to calculate the entropy of.')
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parser.add_argument('--files', nargs='*', type=str, default='', help='Provide file path(s) to calculate the entropy of.')
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# OUTPUT OPTIONS
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parser.add_argument('--simple', nargs='?', type=bool, default=False, help='Determines the explicitness of the output. (True = only entropy shown)')
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# CONVERT OPTIONS
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parser.add_argument('--lower', nargs='?', type=bool, default=False, help='Converts given strings or textfiles to lowercase before calculating.')
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parser.add_argument('--upper', nargs='?', type=bool, default=False, help='Converts given strings or textfiles to uppercase before calculating.')
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parser.add_argument('--squash', nargs='?', type=bool, default=False, help='Removes all whitespaces before calculating.')
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args = parser.parse_args()
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# Prepares the queue of different strings
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queue = []
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# Add all the provided strings to the list
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for string in args.strings:
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queue.append(string)
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# Add all the provided files to the list
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for file in args.files:
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string = getFile(file)
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queue.append(string)
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# Interates over the collected strings and prints the entropies
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for string in queue:
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if args.lower != False:
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string = string.lower()
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elif args.upper != False:
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string = string.upper()
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if args.squash != False:
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string = string.replace(" ", "")
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a, b = calcEntropy(string)
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printEntropy(string, a, b, args.simple)
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