Question

78

RegEx that will match the last occurrence of dot in a string

rated 0 times [ 80] [ 2] / answers: 1 / hits: 110086 / 12 Years ago, thu, june 21, 2012, 12:00:00

I have a filename that can have multiple dots in it and could end with any extension:

tro.lo.lo.lo.lo.lo.png

I need to use a regex to replace the last occurrence of the dot with another string like @2x and then the dot again (very much like a retina image filename) i.e.:

tro.lo.png -> [email protected]

Here's what I have so far but it won't match anything...

str = http://example.com/image.png;

str.replace(/.([^.]*)$/,  @2x.);

any suggestions?

Answers

Only authorized users can answer the question. Please sign in first, or register a free account.

richardaydenc

Add To Favorites

Follow

Total Points: 148

Total Questions: 125

Total Answers: 98

Location: Seychelles

Member since Mon, Jun 28, 2021

3 Years ago

answered 12 Years ago harleyterryp · Accepted Answer

You do not need a regex for this. String.lastIndexOf will do.

var str = 'tro.lo.lo.lo.lo.lo.zip';

var i = str.lastIndexOf('.');

if (i != -1) {

    str = str.substr(0, i) + @2x + str.substr(i);

}

See it in action.

Update: A regex solution, just for the fun of it:

str = str.replace(/.(?=[^.]*$)/, @2x.);

Matches a literal dot and then asserts ((?=) is positive lookahead) that no other character up to the end of the string is a dot. The replacement should include the one dot that was matched, unless you want to remove it.