Be concise.

Be useful.

All contributions dictatorially edited by webmasters to match personal tastes.

Please do not paste any copyright violating resource.

Please try to avoid dependencies to third-party libraries and frameworks.

Other implementations
import "strings"
x2 := strings.Replace(x, y, z, -1)
substr($a, 5, 2) = "replacement text";
let x2 = x.replace(&y, &z);
import std.array;
auto x2 = x.replace(y,z);  
x2 := StringReplace(x, y, z, [rfReplaceAll]);
var x2 = x.replaceAll(y, z);
x2 = x.gsub(y, z)
x2 = String.replace(x, y, z)
import Data.List
allchanged [] _ _ = []
allchanged input from to = if isPrefixOf from input
  then to ++ allchanged (drop (length from) input) from to
  else head input : allchanged (tail input) from to

x2 = allchanged x y z
x2 = x.replace(y, z)
String x2 = x.replace(y, z);
string x2 = x.Replace(y, z);
x2 = x:gsub(y,z)
X2 = binary:replace(X, Y, Z, [global]).
var x2 = x.replace(new RegExp(y, 'g'), z);