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

Question

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 repla

Answer 1

'tro.lo.lo.lo.lo.lo.png'.replace(/([^\.]+).+(\.[^.]+)/, "$1.@x2$2")

Answer 2

To match all characters from the beginning of the string until (and including) the last occurence of a character use:

^.*\.(?=[^.]*$)  To match the last occurrence of the "." character

^.*_(?=[^.]*$)   To match the last occurrence of the "_" character

Answer 3

working demo http://jsfiddle.net/AbDyh/1/

code

var str = 'tro.lo.lo.lo.lo.lo.zip',
    replacement = '@2x.';
str = str.replace(/.([^.]*)$/, replacement + '$1');

$('.test').html(str);

alert(str);
​

Answer 4

You could simply do like this,

> "tro.lo.lo.lo.lo.lo.zip".replace(/^(.*)\./, "$1@2x");
'tro.lo.lo.lo.lo.lo@2xzip'

Answer 5

Why not simply split the string and add said suffix to the second to last entry:

var arr = 'tro.lo.lo.lo.lo.lo.zip'.split('.');
arr[arr.length-2] += '@2x';
var newString = arr.join('.');

Answer 6

You can use the expression \.([^.]*?):

str.replace(/\.([^.]*?)$/, "@2x.$1");

You need to reference the $1 subgroup to copy the portion back into the resulting string.