[PHP] Whats the difference?

[Conrad11]

Hi there,

What is the difference between these?

$str = 0;

and

$str == 0;

...and where would i use them and why?

Thanks.

 

[Inquisitor]

= is the assignment operator. It's used to assign a value to a variable, for example:

$bar = 1337;
$foo = $bar;

It returns the value that was assigned to the variable on the left, so the following code has the same effect:

$foo = ($bar = 1337);

== is the comparison operator. It's used to compare two values, and returns true if they are equal, false otherwise, for example:

$boolean = $foo == $bar; // $boolean is set to true if $foo and $bar are equal

if ($foo == $bar)
{
    // do something
}

 

[robmiller]

Inquisitor's second point looks useless, but is actually really useful when you want to initialise a load of variables to the same value:

$foo = $bar = $baz = $mung = null;