Remove all occurrences except last?

Question

I want to remove all occurrences of substring = . in a string except the last one.

E.G:

1.2.3.4

should become:

Answer 1

You can do something like this:

var str = '1.2.3.4';
var last = str.lastIndexOf('.');
var butLast = str.substring(0, last).replace(/\./g, '');
var res = butLast + str.substring(last);

Live example:

• http://jsfiddle.net/qwjaW/

Answer 2

You could reverse the string, remove all occurrences of substring except the first, and reverse it again to get what you want.

Answer 3

A replaceAllButLast function is more useful than a removeAllButLast function. When you want to remove just replace with an empty string:

function replaceAllButLast(str, pOld, pNew) {
  var parts = str.split(pOld)
  if (parts.length === 1) return str
  return parts.slice(0, -1).join(pNew) + pOld + parts.slice(-1)
}

var test = 'hello there hello there hello there'
test = replaceAllButLast(test, ' there', '')

console.log(test) // hello hello hello there