php map reduce.MD

Sample Code of PHP in map reduce style

Tueday: 2560/Jan/24 (2017)

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PHP PHP Map Reduce

Filter

• Filter http://php.net/manual/en/function.array-filter.php
• http://www.w3schools.com/php/func_array_filter.asp
• With argument http://stackoverflow.com/questions/5482989/php-array-filter-with-arguments

Reduce

• array_reduce http://php.net/manual/en/function.array-reduce.php

Map

• http://php.net/manual/en/function.array-map.php

PHP Anonymous Function

• http://php.net/manual/en/functions.anonymous.php
• 'use' keyword http://stackoverflow.com/questions/10965454/how-does-the-keyword-use-work-in-php-and-can-i-import-classes-with-it

array_filter.php

<?php

$array1 = ['1','2','3'];
$array2 = ['1','3','5']; 
function intersec($array1, $array2){	
	$ar_ret  = array_filter( $array1 ,
							function ($e) use ($array2){      /* closure , anonymous function*/
								return in_array($e,$array2) ; 
							});
	return $ar_ret;
}

// TET 

$ar_ret = intersec($array1,$array2);
print_r($ar_ret );

/*
Return Print
       Array ( [0] => 1 [2] => 3 )   
*/

array_reduce.php

<?php

$array1 = ['1','2','3'];
$array2 = ['1','4','5'];

$ret = array_reduce($array1,  function($total,$e){
	return $total+ $e ;
},0);

echo $ret ;
$ret = array_reduce($array1,  function($total,$e){
	return $total+ $e ;
},$ret);

echo " / " ;
echo $ret ;

/* NOTE: Print   '6 / 12'  */

array_reduce_with_index.php

<?php

$array1 = ['1','2','3','4'];
$array2 = ['1','3','5','4']; 

function get_count_pos($array1,$array2){
    $idx =  -1 ; 
	return array_reduce($array1, function($total,$a1val) use($array2 , &$idx ){
		$idx ++ ;  /*start from index=0 */
		return $total + ($a1val==$array2[$idx] ? 1 :0) ;
	}, 0 /*init as 0 */ );	
}


// TET 

$ar_ret = get_count_pos($array1,$array2);
print_r($ar_ret );

/* Return print '2' */