BUILT-IN MATHEMATICA SYMBOL

StringCount

StringCount["string", "sub"]
gives a count of the number of times appears as a substring of .

StringCount["string", patt]
gives the number of substrings in that match the general string expression patt.

StringCount["string", {patt₁, patt₂, ...}]
counts the number of occurrences of any of the .

StringCount[{s₁, s₂, ...}, p]
gives the list of results for each of the .

Details and Options Details and Options

The string expression patt can contain any of the objects specified in the notes for StringExpression.
With the default option setting Overlaps->False, overlapping substrings are not treated as separate. With the setting Overlaps->True, StringCount counts substrings that overlap as separate.
With Overlaps->All, multiple substrings that match the same string expression are all counted as separate. With Overlaps->True, only the first such matching substring at a given position is counted as separate.
Setting the option IgnoreCase->True makes StringCount treat lowercase and uppercase letters as equivalent.
StringCount["string", RegularExpression["regex"]] gives the number of substrings matching the specified regular expression.