MATLAB Programming Fundamentals - MathWorks

For more information, see “Lookahead Assertions in Regular Expressions” on page 2-57.

Logical and Conditional Operators

Logical and conditional operators allow you to test the state of a given condition, and then

use the outcome to determine which pattern, if any, to match next. These operators

support logical OR and if or if/else conditions. (For AND conditions, see “Lookaround

Assertions” on page 2-51.)

Conditions can be tokens on page 2-52, lookaround assertions on page 2-51, or dynamic

expressions on page 2-54 of the form (?@cmd). Dynamic expressions must return a

logical or numeric value.

Conditional Operator Description Example

expr1|expr2 Match expression expr1 or

expression expr2.

If there is a match with expr1,

then expr2 is ignored.

'(let|tel)\w+' matches words

that start with let or tel.

(?(cond)expr) If condition cond is true, then

match expr.

'(?(?@ispc)[A-Z]:\\)'

matches a drive name, such as C:\,

when run on a Windows system.

(?(cond)expr1|

expr2)

If condition cond is true, then

match expr1. Otherwise, match

expr2.

'Mr(s?)\..*?(?(1)her|his)

\w*' matches text that includes

her when the text begins with Mrs,

or that includes his when the text

begins with Mr.

Token Operators

Tokens are portions of the matched text that you define by enclosing part of the regular

expression in parentheses. You can refer to a token by its sequence in the text (an ordinal

token), or assign names to tokens for easier code maintenance and readable output.

Ordinal Token Operator Description Example

(expr) Capture in a token the characters

that match the enclosed

expression.

'Joh?n\s(\w*)' captures a token

that contains the last name of any

person with the first name John or

Jon.

2 Program Components