How Can I Efficiently Count Overlapping String Occurrences in Python?

Overlapping String Occurrence Counting in Python

When it comes to counting string occurrences, overlooking overlaps can lead to incorrect results. One common approach is to loop over the string character by character, but this can be inefficient for larger strings.

Is There a Better Way?

Yes, there is a more efficient solution using the find() method, which operates in C. Here's the improved code:

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

How it Works

• The string.find() method searches for the first occurrence of sub starting from position start in the string.
• The loop continues until no more occurrences are found.
• The start position is incremented by one after each occurrence to check for overlaps.

Usage Example

For example, counting the occurrences of "11" in the string "1011101111" using this method would yield the same result of 5, but with improved efficiency.

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