How to call a function from a string stored in a variable?

Question

I need to be able to call a function, but the function name is stored in a variable, is this possible? e.g:

function foo ()
{
  //code here
}

function bar ()
{
          


        

Answer 1

What I learnt from this question and the answers. Thanks all!

Let say I have these variables and functions:

$functionName1 = "sayHello";
$functionName2 = "sayHelloTo";
$functionName3 = "saySomethingTo";

$friend = "John";
$datas = array(
    "something"=>"how are you?",
    "to"=>"Sarah"
);

function sayHello()
{
echo "Hello!";
}

function sayHelloTo($to)
{
echo "Dear $to, hello!";
}

function saySomethingTo($something, $to)
{
echo "Dear $to, $something";
}

1. To call function without arguments

   // Calling sayHello()
   call_user_func($functionName1); 
   

   Hello!

2. To call function with 1 argument

   // Calling sayHelloTo("John")
   call_user_func($functionName2, $friend);
   

   Dear John, hello!

3. To call function with 1 or more arguments This will be useful if you are dynamically calling your functions and each function have different number of arguments. This is my case that I have been looking for (and solved). call_user_func_array is the key

   // You can add your arguments
   // 1. statically by hard-code, 
   $arguments[0] = "how are you?"; // my $something
   $arguments[1] = "Sarah"; // my $to
   
   // 2. OR dynamically using foreach
   $arguments = NULL;
   foreach($datas as $data) 
   {
       $arguments[] = $data;
   }
   
   // Calling saySomethingTo("how are you?", "Sarah")
   call_user_func_array($functionName3, $arguments);
   

   Dear Sarah, how are you?

Yay bye!