def incidenceOfCoincidence(sequence):
if (len(sequence) > 1):
F = Frequency()
F.count(sequence)
IncOfCoinc = 0
FreqNum = 0
length = len(sequence)
for i in range(0,26):
FreqNum = F.getNthNum(i)
IncOfCoinc = IncOfCoinc + (FreqNum*(FreqNum - 1))
IncOfCoinc = (IncOfCoinc / (length*(length - 1)))
return IncOfCoinc
else:
return 0
def incidence_of_coincidence(sequence):
'''
Processes and return the incidence of coincidence of a given substring of the ciphertext
'''
if (len(sequence) > 1):
F = Frequency()
F.count(sequence)
IncOfCoinc = 0
FreqNum = 0
length = len(sequence)
for i in range(0,26):
FreqNum = F.getNthNum(i)
IncOfCoinc = IncOfCoinc + (FreqNum*(FreqNum - 1))
IncOfCoinc = (IncOfCoinc / (length*(length - 1)))
return IncOfCoinc
else:
return 0
