Find the substrings matching a pattern:

Return only the named wildcard character in each substring:

Use the operator form of StringCases:

Use string patterns:

Use a regular expression:

Use pattern matching for dates:

Mixed regular expressions and string patterns:

Rules to extract values corresponding to matching substrings:

Include only the two first strings that match:

Occurrences in either substring:

StringCases automatically threads over lists of strings:

Find codon-length subsequences in a DNA sequence:

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

The "Y" 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:

Extract phone numbers from a text:

Find the sequence of section numbers in the US Constitution:

Find the numbers of amendments to the Constitution:

Primes whose digits are all consecutive:

StringCount gives the number of matching substrings:

The length of matching substrings:

Use StringPosition to get the position of matching substrings:

Check:

Use :> rather than -> if the right-hand side of a rule contains string operations:

Using -> in such cases leads to immediate evaluation and possible error messages:

Find the sequence of words in the US Constitution:

Total number of words:

Number of distinct words:

Logarithmic frequency distribution of words:

Ten most common words: