Replace last occurrence of character in string

Question

Is there an easy way in javascript to replace the last occurrence of an '_' (underscore) in a given string?

Answer 1

You don't need jQuery, just a regular expression.

This will remove the last underscore:

var str = 'a_b_c';  console.log(  str.replace(/_([^_]*)$/, '$1')  ) //a_bc

This will replace it with the contents of the variable replacement:

var str = 'a_b_c',      replacement = '!';    console.log(  str.replace(/_([^_]*)$/, replacement + '$1')  ) //a_b!c

Answer 2

No need for jQuery nor regex assuming the character you want to replace exists in the string

Replace last char in a string

str = str.substring(0,str.length-2)+otherchar

Replace last underscore in a string

var pos = str.lastIndexOf('_'); str = str.substring(0,pos) + otherchar + str.substring(pos+1) 

or use one of the regular expressions from the other answers

var str1 = "Replace the full stop with a questionmark."  var str2 = "Replace last _ with another char other than the underscore _ near the end"    // Replace last char in a string    console.log(    str1.substring(0,str1.length-2)+"?"  )    // alternative syntax  console.log(    str1.slice(0,-1)+"?"  )    // Replace last underscore in a string     var pos = str2.lastIndexOf('_'), otherchar = "|";  console.log(    str2.substring(0,pos) + otherchar + str2.substring(pos+1)  )  // alternative syntax    console.log(    str2.slice(0,pos) + otherchar + str2.slice(pos+1)  )