Description:
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The manual page http://www.php.net/manual/en/language.operators.array.php describes several operators available which work on array variables. This includes the addition (+) operator, which allows us to merge two arrays.

I would suggest that a subtraction operator would also be useful.

For example, let us say we have two arrays, one of which is a full list of available items, and the other is a list of items which have been used, and I want to find the list of items which haven't been used. An array subtraction operator would help with this.

Test script:
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<?php
//suggested use for array subtraction operator.

$full_list = array('de'=>'some data', 'gr'=>'some data', 'tt'=>'some data'); //etc...
$used_list = array('gr'=>'some data'); //etc...

$unused_list = $full_list - $used_list; //would contain 'de' and 'tt', but not 'gr'.
?>

Expected result:
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$unused_list would contain the array elements from $full_list minus those present in $used_list. In the example code, this would mean $unused_list would contain 'de' and 'tt', but not 'gr'.


Actual result:
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This is a feature suggestion, so the above code does not currently run.