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PHP PHP Functions Function Returns and More PHP Variable Functions

Posted by ammarkhan
.a{fill-rule:evenodd;}techdegree
ammarkhan
Front End Web Development Techdegree Student 21,661 Points

How does a function can be called without set of ()

I am confused over how do we call on a function without set of () , in the video the call to function is done by

$func = answer;
echo $func ;

Whereas i what i know is that a function is called like

$func = answer();

echo $func;

So why is the video other way around without ()

2 Answers

David Makowski
David Makowski
13,676 Points
David Makowski
David Makowski
13,676 Points

In the second version the parenthesis are kind of included in the $func variable. So after that it's possible to call it without them, because what you are actually calling when you write 

echo $func;

is answer()

Dan Avramescu
Dan Avramescu
11,286 Points
Dan Avramescu
Dan Avramescu
11,286 Points

i think the $func here acts as a callback for echo, correct me if i'm wrong

Hugo Paz
Hugo Paz
15,622 Points
Hugo Paz
Hugo Paz
15,622 Points

Hi Ammar,

If you notice in the video, he uses parenthesis on the variable, like this:

$func = 'answer';

$func();
ammarkhan
.a{fill-rule:evenodd;}techdegree
ammarkhan
Front End Web Development Techdegree Student 21,661 Points

But why not just use 

$func();

for all of the time < php 4, i been seeing like that of echo out function, but '''php $function = 'answer'; $function(); '''' what's the difference and why use one over the other?

Hugo Paz
Hugo Paz
15,622 Points
Hugo Paz
Hugo Paz
15,622 Points

You use a variable with the name of a function.

Here's an example:

<?php

function printName($name){
  echo $name . '<br/>';
}

$name = 'Hugo';
//I gave a different variable name in this case to make it clear what this variable is. We pass it the name of the function as a string.
$printFunction = 'printName';

//We use the variable to call the printName function
$printFunction('Ted');

printName($name);

?>