Programming |

A regular expression is a string of characters that defines a certain pattern. You would normally use a regular expression in searching through text for a group of words that matches this pattern, perhaps while parsing program input, or while processing a block of text.

The string `'Joh?n\w*'`

is an example of a regular expression. It defines a pattern that starts with the letters `Jo`

, is optionally followed by the letter `h`

(indicated by `'h?'`

), is then followed by the letter `n`

, and ends with any number of non-whitespace characters (indicated by `'\w*'`

). This pattern matches any of the following:

MATLAB supports most of the special characters, or *metacharacters*, commonly used with regular expressions and provides several functions to use in searching and replacing text with these expressions.

This section discusses the following topics:

- MATLAB Regular Expression Functions
- Elements of an Expression
- Tokens
- Handling Multiple Strings
- Operator Summary

**MATLAB Regular Expression Functions**

Several MATLAB functions support searching and replacing characters using regular expressions:

Function |
Description |

`regexp` |
Match regular expression. |

`regexpi` |
Match regular expression, ignoring case. |

`regexprep` |
Replace string using regular expression. |

See the function reference pages to obtain more information on these functions. For more information on how to use regular expressions in general, consult a reference on that subject.

Shell Escape Functions | Elements of an Expression |

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