• Python

x2 = x.replace(y, z)

• C++

constexpr std::string ReplaceAllCopy(const std::string& x, const std::string& y, const std::string& z) {
	auto x2 = x;
	size_t i = 0;

	while (true) {
		i = x2.find(y, i);
		if (i == std::string::npos) break;
		x2.replace(i, y.length(), z);
	}
	return x2;
}

• C++

std::stringstream s;
std::regex_replace(std::ostreambuf_iterator<char>(s), x.begin(), x.end(), y, z);
auto x2 = s.str()

• C#

string x2 = x.Replace(y, z, StringComparison.Ordinal);

• D

auto x2 = x.replace(y,z);  

• Dart

var x2 = x.replaceAll(y, z);

• Elixir

x2 = String.replace(x, y, z)

• Erlang

X2 = binary:replace(X, Y, Z, [global]).

• Fortran

  character(len=:), allocatable :: x
  character(len=:), allocatable :: x2
  character(len=:), allocatable :: y,z
  integer :: j, k
  k=1
  do
     j = index(x(k:),y)
     if (j==0) then
        x2 = x2 // x(k:)
        exit
     end if
     if (j>1) then
        x2 = x2 // x(k:j+k-2)
     end if
     x2 = x2 // z
     k = k + j + len(y) - 1
  end do

• Go

x2 := strings.ReplaceAll(x, y, z)

• Go

x2 := strings.Replace(x, y, z, -1)

• Haskell

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

• JS

var x2 = x.replace(new RegExp(y, 'g'), z);

• JS

const x2 = x.replaceAll(y, z);

• Java

String x2 = x.replace(y, z);

• Lua

x2 = x:gsub(y,z)

• PHP

$x2 = str_replace($y, $z, $x);

• Pascal

x2 := StringReplace(x, y, z, [rfReplaceAll]);

• Perl

my $x2 = $x =~ s/\Q$y/$z/gr;

• Ruby

x2 = x.gsub(y, z)

• Rust

let x2 = x.replace(&y, &z);

• VB

Dim x2 As String = x.Replace(y, z, StringComparison.Ordinal)