Javascript Regex: replacing the last dot for a comma

Question

I have the following code:

var x = "100.007"
x = String(parseFloat(x).toFixed(2));
return x
=> 100.01

This works awesomely just how I want it to work. I just want a tiny addition, which is something like:

var x = "100,007"
x.replace(",", ".")
x.replace
x = String(parseFloat(x).toFixed(2));
x.replace(".", ",")
return x
=> 100,01

However, this code will replace the first occurrence of the ",", where I want to catch the last one. Any help would be appreciated.

Answer 1

You can do it with a regular expression:

x = x.replace(/,([^,]*)$/, ".$1");

That regular expression matches a comma followed by any amount of text not including a comma. The replacement string is just a period followed by whatever it was that came after the original last comma. Other commas preceding it in the string won't be affected.

Now, if you're really converting numbers formatted in "European style" (for lack of a better term), you're also going to need to worry about the "." characters in places where a "U.S. style" number would have commas. I think you would probably just want to get rid of them:

x = x.replace(/\./g, '');

When you use the ".replace()" function on a string, you should understand that it returns the modified string. It does not modify the original string, however, so a statement like:

x.replace(/something/, "something else");

has no effect on the value of "x".