Question

What is Greedy vs NonGreedy Regex.

Answer 1

In the below string if you do a standard greedy regex of <[\S|\s]*>" it will find the entire string. A non greedy regex "<[\S|\s]*?>" will only find the xml tags.

 

<sometag>asdfaf</sometag>

<sometag>asdfaf</sometag>

<sometag>asdfaf</sometag>

<sometag>asdfaf</sometag>

<sometag>asdfaf</sometag>

<sometag>asdfaf</sometag>

<sometag>asdfaf</sometag>

The ? in the nonGreedy regex defines it and nonGreedy.

 

Example using a javascript replace

 

//Create a Java String Note all qie functions message.getNode, qie.* functions return a Java string)

var value = new java.lang.String('<sometag>asdfaf</sometag>\n<sometag>asdfaf</sometag>\n<sometag>asdfaf</sometag>\n<sometag>asdfaf</sometag>\n<sometag>asdfaf</sometag>\n<sometag>asdfaf</sometag>\n<sometag>asdfaf</sometag>');

//Convert the java string to a javascript string

var javaScriptString = '' + value;

//do a greedy regex replace with the javascript replace

qie.debug('greedy replace:\n' + javaScriptString.replace(/(<[\S|\s]*>)/gm, ''));

//do a nonGreedy regex replace with a javascript replace

qie.debug('nongreedy replace:\n' + javaScriptString.replace(/(<[\S|\s]*?>)/gm, ''));