How to remove all characters from a string

Question

How can I remove all characters from a string that are not letters using a JavaScript RegEx?

Answer 1

RegEx instance properties used g , i

global : Whether to test the regular expression against all possible matches in a string, or only against the first.

ignoreCase : Whether to ignore case while attempting a match in a string.

RegEx special characters used [a-z] , +

[^xyz] : A negated or complemented character set. That is, it matches anything that is not enclosed in the brackets. You can specify a range of characters by using a hyphen.

For example, [abcd] is the same as [a-d]. They match the 'b' in "brisket" and the 'c' in "chop".

+ : Matches the preceding item 1 or more times. Equivalent to {1,}.

JavaScript string replace method syntax

str.replace(regexp|substr, newSubStr|function[, Non-standard flags]);

The non-standard flags g & i can be passed in the replace syntax or built into the regex. examples:

var re = /[^a-z]+/gi;   var str = "this is a string";   var newstr = str.replace(re, "");   print(newstr);

var str = "this is a string";   var newstr = str.replace(/[^a-z]+/, "", "gi");   print(newstr);

To match whitespace characters as well \s would be added to the regex [^a-z\s]+.

JavaScript Reference