MATLAB Programming Fundamentals - MathWorks

Dynamic Regular Expressions

In this section...

“Introduction” on page 2-69

“Dynamic Match Expressions — (??expr)” on page 2-70

“Commands That Modify the Match Expression — (??@cmd)” on page 2-71

“Commands That Serve a Functional Purpose — (?@cmd)” on page 2-72

“Commands in Replacement Expressions — ${cmd}” on page 2-75

Introduction

In a dynamic expression, you can make the pattern that you want regexp to match

dependent on the content of the input text. In this way, you can more closely match

varying input patterns in the text being parsed. You can also use dynamic expressions in

replacement terms for use with the regexprep function. This gives you the ability to

adapt the replacement text to the parsed input.

You can include any number of dynamic expressions in the match_expr or

replace_expr arguments of these commands:

regexp(text, match_expr)

regexpi(text, match_expr)

regexprep(text, match_expr, replace_expr)

As an example of a dynamic expression, the following regexprep command correctly

replaces the term internationalization with its abbreviated form, i18n. However, to

use it on a different term such as globalization, you have to use a different

replacement expression:

match_expr = '(^\w)(\w*)(\w$)';

replace_expr1 = '$118$3';

regexprep('internationalization', match_expr, replace_expr1)

ans =

'i18n'

replace_expr2 = '$111$3';

regexprep('globalization', match_expr, replace_expr2)

Dynamic Regular Expressions