Count substrings with the Replace function

Count substrings with the Replace function

You can often use the Replace function in a smewhat unorthodox ways to simplify (and sometimes optimize) your code. For example, in order to count the number of occurrences of a substring inside another string you usually need a loop based on the InStr function:

Dim i As Long, count As Longi = InStr(source, search)Do While i    count = count + 1    i = InStr(i + 1, source, search)Loop

Here’s is a one-liner that does exactly the same. The trick is to replace each substring with another string that is one character longer, and then determine the difference between the obtained string and the original string. This number is equal to the number of substitutions done, and therefore equal to the number of substrings found. (Note that the code is more concise but a little slower than the previous approach).

count = Len(Replace(Source, Search, Search & "*")) - Len(Source)


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