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Array Operators

**Array Operators**
Example	Name	Result
$a + $b	Union	Union of $a and $b.
$a == $b	Equality	`TRUE` if $a and $b have the same key/value pairs.
$a === $b	Identity	`TRUE` if $a and $b have the same key/value pairs in the same order and of the same types.
$a != $b	Inequality	`TRUE` if $a is not equal to $b.
$a <> $b	Inequality	`TRUE` if $a is not equal to $b.
$a !== $b	Non-identity	`TRUE` if $a is not identical to $b.

The + operator appends elements of remaining keys from the right handed array to the left handed, whereas duplicated keys are NOT overwritten.

  <?php 
$a  = array( "a"  =>  "apple" ,  "b"  =>  "banana" ); 
 $b  = array( "a"  =>  "pear" ,  "b"  =>  "strawberry" ,  "c"  =>  "cherry" ); 
 
 $c  =  $a  +  $b ;  // Union of $a and $b 
 echo  "Union of \$a and \$b: \n" ; 
 var_dump ( $c ); 
 
 $c  =  $b  +  $a ;  // Union of $b and $a 
 echo  "Union of \$b and \$a: \n" ; 
 var_dump ( $c ); 
 ?>

When executed, this script will print the following:

Union of $a and $b:
array(3) {
  ["a"]=>
  string(5) "apple"
  ["b"]=>
  string(6) "banana"
  ["c"]=>
  string(6) "cherry"
}
Union of $b and $a:
array(3) {
  ["a"]=>
  string(4) "pear"
  ["b"]=>
  string(10) "strawberry"
  ["c"]=>
  string(6) "cherry"
}

Elements of arrays are equal for the comparison if they have the same key and value.

Example #1 Comparing arrays

  <?php 
$a  = array( "apple" ,  "banana" ); 
 $b  = array( 1  =>  "banana" ,  "0"  =>  "apple" ); 
 
 var_dump ( $a  ==  $b );  // bool(true) 
 var_dump ( $a  ===  $b );  // bool(false) 
 ?>

See also the manual sections on the Array type and Array functions.

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