From Ajax Patterns

This page overviews regular expressions (regexp/regex) in Javascript.

Contents 1 References 2 Idioms 2.1 Get an array of all matches 2.2 Run a string substitution/replacement 2.3 Split up a string, expressing the divider as a regular expression 2.4 Assign to Groupings and remix initial string 3 Gotchas

References

• The examples below are taken from the Javascrit Kit Tutorial

• W3Schools replace() function

Idioms

Get an array of all matches

  var string1="Peter has 8 dollars and Jane has 15"
  parsestring1=string1.match(/\d+/g) //returns the array [8,15]

Run a string substitution/replacement

 var string2="(304)434-5454"
 parsestring2=string2.replace(/[\(\)-]/g, "") //Returns "3044345454" (removes "(", ")", and "-")

Split up a string, expressing the divider as a regular expression

 var string3="1,2, 3,  4,   5"
 parsestring3=string3.split(/\s*,\s*/) //Returns the array ["1","2","3","4","5"]

Assign to Groupings and remix initial string

 var objRegExp = /(\w+)\s(\w+)/;
 var strFullName = "Jane Doe";
 var strReverseName = strFullName.replace(objRegExp, "$2, $1");

Gotchas

• Regex functions generally return values, rather than mutate the original value. To mutate a string, e.g. run a substitution, you'll usually do something like x = x.replace(/so last week/, "new, improved, beta 2.0").
• Remember to use the /g flag for global substitutions. e.g. x.replace(/dirty/g, "clean"). Otherwise, only one dirty will be cleaned.