How Can I Efficiently Count Overlapping Substring Occurrences in Python?

Counting String Occurrences with Overlapping Occurrences in Python

The question pertains to finding an efficient Python method to count occurrences of a specific substring, allowing for overlaps. One suggested approach involves an iterative search:

def function(string, str_to_search_for):
  count = 0
  for x in xrange(len(string) - len(str_to_search_for) + 1):
    if string[x:x+len(str_to_search_for)] == str_to_search_for:
      count += 1
  return count

However, a potentially faster method utilizes the Python find() function to perform the search in C:

def occurrences(string, sub):
  count = start = 0
  while True:
    start = string.find(sub, start) + 1
    if start > 0:
      count += 1
    else:
      return count

This approach leverages the computational efficiency of C by performing the search in a lower-level language. By using the while loop, it continues to search for occurrences of the substring, incrementing the count variable as it finds them. Ultimately, it returns the total count of occurrences, including those that overlap.

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