正则表达式-在不是字母的任何字符之前添加空格

Question

I have tried many things and am looking for a space to be added after any character that is not a letter. Currently I can replace all non letter characters with a space, but I want a space before the character is matched. At the moment I have:

var str = 'div#some_id.some_class';
str = str.replace(/[^A-Za-z0-9]/g, ' ');

This provides me with the following,

div some_id some_class

however I am looking for the result to be div #some_id .some_class

Any help would be greatly appreciated.

Answer 1

You can use a negative lookahead for this:

str = str.replace(/(?!\w|$)/g, ' ')
//=> "div #some_id .some_class"

(?!\\w|$) will match positions where next character is not alpha0numeral or end of line.

Answer 2

Use groups and substitution

 var str = 'div#some_id.some_class'; str = str.replace(/([^A-Za-z0-9])/g, ' $1'); console.log(str); 

Answer 3

You can try this :

str = str.replace(/([^a-zA-Z0-9_])/g, ' $1') //Omit 0-9 if you you want a space before them too

//OUTPUT: div #some_id .some_class

Answer 4

If you have an exact subset in mind, you'd probably be better of to specify just (but exactly) that (since Unicode has quite some characters you might not have even thought about.. think about things like unintended föóbàr to f ö ób àr , not even mentioning languages that don't really use Az ):

 var str = 'div#some_id.some_class'; str = str.replace( /[.#]/g // add your exact subset to match on between the [ ] , ' $&' // $& inserts the matched substring (no capturing group needed) ); console.log(str); 

Answer 5

Also try at \\b word boundaries, where a \\W non word character is ahead:

(?=\\W)\\b and replace matched position with a space ( regex101 ).