MATLAB Programming

3 Basic Program Components
Conditions Based on a Lookaround Match
Lookaround statements look for text that either precedes or follows an
expression. If this lookaround text is located, then MATLAB proceeds to
match the expression. You can also use lookarounds in conditional statements.
In this case, if the lookaround text is located, then MATLAB considers the
conditiontobemetandmatchestheassociatedexpression.Iftheconditionis
not met, then MATLAB matches the else part of the expression.
Conditions Based on Return Values
MATLAB supports different types of dynamic expressions. One type of
dynamic expression, having the form (?@cmd), enables you to execute a
MATLAB command (shown here as cmd) while matching an expression.
You can use this type of dynamic expression in a conditional statement if
the command in the expression returns a numeric value. The condition is
considered to be met if the return value is nonzero.
Dynamic Regular Expressions
In a dynamic expression, you can make the pattern that you want regexp to
match dependent on the content of the input string. In this way, you can
more closely match varying input patterns in the string being parsed. You
can also use dynamic expressions in replacement strings 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(string, match_expr)
regexpi(string, match_expr)
regexprep(string, match_expr, replace_expr)
MATLAB supports three types of dynamic operators for use in a match
expression. See “Dynamic Operators for the Match Expression” on page 3-60
for more information.
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