You can use this function to parse a string looking for specific parts, which can then be replaced by the new string that you have specified in all places that they occur.
string_replace_all(str, substr, newstr);
Argument Description str The string to be copied. substr The substring within the string to be replaced in all instances. newstr The new substring to replace the previous one(s).
str1 = "Hexxo Worxd";
str2 = string_replace_all(str1, "x", "l");
This will set str2 to str1, but with its instances of "x" replaced with "l", resulting in str2 being "Hello World".