Returns a list of strings that contain the given substring (case insensitive), allowing for regular expressions.
Available in version 6.3.0 and later.
function str_match_ic_regex ( string_array [*] : string, expression  : string ) return_val [*] : string
A string array of any dimensionality.expression
The string expression to be matched, with possible regex ("regular expressions") syntax included.
This function returns an array of strings with every occurrence of expression matched in string_array. Unlike str_match_ic, regular expressions are allowed.
If there is no expression matched in string_array, the default string missing value ("missing") will be returned.
Note that str_match_ic_regex is case INSENSITIVE. Use str_match_regex if you need case sensitivity.
A full description of the syntax and capabilities of regular expressions is beyond the scope of this document. See the Unix/POSIX man page for REGEX (7) or similar documentation for a complete explanation, noting that NCL's implementation uses the "modern" form of regular expressions. In reality only a very small subset of the full functionality will be needed for the purposes of this function.
For those not familiar with the topic one basic point is that unlike the use in a directory listing of the asterisk ('*') as a wildcard standing for any number of arbitrary characters, the equivalent operator in a regular expression consists of the two character sequence: '.*'.
Assume you have a mix of abbreviated month names with the form "mmm" and "MMM", and you want to return all occurrences of "jan" and "JAN"
months = (/"jan","feb","MAR","JAN","FEB","MAR","jan","feb","mar"/) jan_ic = str_match_ic_regex(months,"jan") ; (/"jan","JAN","jan"/) jan_sc = str_match_regex(months,"jan") ; (/"jan","jan"/)