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Top Forums UNIX for Beginners Questions & Answers Perl/Array Sorting : Can someone please explain below code $h{$_}++ Post 303032307 by Tanu on Friday 15th of March 2019 05:38:28 AM
Old 03-15-2019
Perl/Array Sorting : Can someone please explain below code $h{$_}++

Code:
sub uniq {
    my %h;
    return grep { !$h{$_}++ } @_
}

The above code is to remove duplicates from array.

I am having hard time understanding below things (basically around highlighted code in bold)-

when was the value inserted in hash?
and are we only adding a key in Hash not values?
Code:
$h{$_}++

what "++" means here
 

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ARRAY_CHUNK(3)								 1							    ARRAY_CHUNK(3)

array_chunk - Split an array into chunks

SYNOPSIS
array array_chunk (array $array, int $size, [bool $preserve_keys = false]) DESCRIPTION
Chunks an array into arrays with $size elements. The last chunk may contain less than $size elements. PARAMETERS
o $array - The array to work on o $size - The size of each chunk o $preserve_keys - When set to TRUE keys will be preserved. Default is FALSE which will reindex the chunk numerically RETURN VALUES
Returns a multidimensional numerically indexed array, starting with zero, with each dimension containing $size elements. ERRORS
/EXCEPTIONS If $size is less than 1 E_WARNING will be thrown and NULL returned. EXAMPLES
Example #1 array_chunk(3) example <?php $input_array = array('a', 'b', 'c', 'd', 'e'); print_r(array_chunk($input_array, 2)); print_r(array_chunk($input_array, 2, true)); ?> The above example will output: Array ( [0] => Array ( [0] => a [1] => b ) [1] => Array ( [0] => c [1] => d ) [2] => Array ( [0] => e ) ) Array ( [0] => Array ( [0] => a [1] => b ) [1] => Array ( [2] => c [3] => d ) [2] => Array ( [4] => e ) ) SEE ALSO
array_slice(3). PHP Documentation Group ARRAY_CHUNK(3)
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