!== operator

[Scheisskopf]

What is the !== or === (i guess) operator all about?

[lilleman]

Hi,

It's used to check whether or not two values are identical (if both the value and the datatype is the same).

if( 0 == false ) echo 'this will be printed';
if( 0 === false ) echo 'this will not...'; 

[melancholic]

=== is identity
!== is nonidentity

compares the value of the variable(s) and type of the value of the variable(s) in an expression

identity returns true on match and false on mismatch
non-identity returns true on mismatch and false on match

regards,

melan'

[Scheisskopf]

thanks

[Atealtha]

Is there a difference between != and !==? = and == does, but I don't see how != can mean "if it doesn't assign" logic.

[someonewhois]

Is there a difference between != and !==? = and == does, but I don't see how != can mean "if it doesn't assign" logic.

There's a huge difference between != and !==. You have to remember that != and == are in the same field, and !== and === are in the same field. The = and == comparison is a different story all together. = is an assignment operator, != and !== are both comparison operators just like == and ===.

   <?php
   $a = 5; // Assignment operator.
   if ($a == 5)
   {
       echo 'We WILL get here.';
   }
   if ($a === 5)
   {
       echo 'We will also get here';
   }
   if ($a === '5')
   {
      echo 'We will NOT get here.';
   }
   if ($a !== 3)
   {
      echo 'WILL get here';
   }
   if ($a !== '5')
   {
       echo 'Will get here.';
   }
   if ($a != '5')
   {
     echo 'Will NOT get here.';
   }
  if ($a = 3)
  {
 echo 'This will always return true, as this was an ASSIGNMENT operator. This if statemen just overwrote $a to be 3 instead of 5, and the assignment ends up returning true.';
  }

[melancholic]

Hi there,

just to give a flat definition for the operators:

=== called the identity operator
checks both value AND dataType of value when doing a comparison returns true on match

!== called the nonIdentity operator
checks both value AND dataType of value when doing a comparison returns true on mismatch

== is called the Equality operator
checks values (only) when doing a comparison returns true on match

!= is called the Inequality operator
checks values (only) when doing a comparison returns true on mismatch

<> (also) called inequality operator
checks values (only) when doing a comparison returns true on mismatch

regards,

'cholic

[dmsuperman]

It compares variables. It is the same as != and ==, except it also checks if they are the same type of variable.

[karnetics]

try this piece of code!!!

<?php
   
   switch ($a = 5)// Assignment operator.
   {
        case 1;
        $a == 5;
           echo 'We WILL get here.';
           break;

        case 2;
           $a === 5;
           echo 'We will also get here';
           break;
           
           
        case 3;
         $a === '5';
        echo 'We will NOT get here.';
        break;
   //repeated steps until the end of your code
   }
echo 'This will always return true, as this was an ASSIGNMENT operator. This if statemen just overwrote $a to be 3 instead of 5, and the assignment ends up returning true.';

  ?>