Find the starting and ending positions at which "XYZ" occurs in a string:

Find where any pairs of identical characters occur:

Use the operator form of StringPosition:

StringPosition gives substring positions in the form used by functions like StringTake:

Find the position of the first occurrence of "XYZ":

StringPosition by default includes overlaps:

Use Overlaps->False to exclude overlaps:

Find the position of a subsequence within a DNA sequence:

Use a wildcard in the pattern found in a given biomolecular sequence:

The "N" is a degenerate letter and is not a wildcard except in biomolecular sequences:

Additional wraparound matches may be found in circular biomolecular sequences:

Match only literal degenerate letter occurrences using Verbatim:

Find positions of pairs of identical letters in a concatenation sequence:

Find an analogous curve for triples:

Find the positions of the word "president" in the US Constitution:

Use StringTake to extract substrings found by StringPosition:

StringCases by default excludes overlaps:

Use StringReplacePart to replace at positions found by StringPosition:

Lists of string patterns in StringPosition are sometimes not the same as pattern alternatives: