String count with overlapping occurrences

Question

What\'s the best way to count the number of occurrences of a given string, including overlap in Python? This is one way:

def function(string, str_to_search_f         


        

Answer 1

Given

sequence = '1011101111'
sub = "11"

Code

In this particular case:

sum(x == tuple(sub) for x in zip(sequence, sequence[1:]))
# 5

More generally, this

windows = zip(*([sequence[i:] for i, _ in enumerate(sequence)][:len(sub)]))
sum(x == tuple(sub) for x in windows)
# 5

or extend to generators:

import itertools as it


iter_ = (sequence[i:] for i, _ in enumerate(sequence))
windows = zip(*(it.islice(iter_, None, len(sub))))
sum(x == tuple(sub) for x in windows)

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Alternative

You can use more_itertools.locate:

import more_itertools as mit


len(list(mit.locate(sequence, pred=lambda *args: args == tuple(sub), window_size=len(sub))))
# 5