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up vote 1 down vote favorite

I'm hoping there's an easy way to do this without tons and tons of loops.

I have a matrix in the following manner:

    Weight1 Weight2 Weight3 .... WeightN
Jan    1       3       5            4
Feb    10      12      15          11
Mar    5       7       4            3
Apr    10      15      7            3

Assuming the following array:

$arrayMonths = array(
       'jan' => array(1, 3, 5,4)
       'feb' => array(10,12,15,11)
       'mar' => array(5, 7, 4, 3)
       'apr' => array(10,15,7,3)
    );

What is the best way for me to get the the max for each row: jan = 5 feb = 15 mar = 7 apr = 15

Thanks

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1  
What have you tried? –  Jack Maney Apr 27 '12 at 6:24
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4 Answers

up vote 1 down vote

Use the max() function:

foreach($arrayMonths as $month => $row)
{
    echo $month . ": " . max($row) . "<br />";
}
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up vote 1 down vote 
foreach ($arrayMonths as $month => $array) {
    // store the max of each month for later
    // $max['jan'] = 5
    $max[$month] = max($array);

    // or print it out
    echo $month. ' => '. max($array);
}

From the max() PHP Docs

If you need to go further with sorting you can check out here for more information PHP Array Sorting

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up vote 0 down vote

Try this:

<?php
function getMax( $v, $k ) {
    global $arrayMonths;

    $arrayMonths[ 'max' ][$k] = max($v);
}

$arrayMonths = array(
   'jan' => array(1, 3, 5,4),
   'feb' => array(10,12,15,11),
   'mar' => array(5, 7, 4, 3),
   'apr' => array(10,15,7,3)
);

array_walk( $arrayMonths, 'getMax' );

// Now $arrayMonths['max'] will contain all max values for each key
?>

Hope this helps.

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up vote 0 down vote accepted

I found the perfect algorithm: Basically use a recursive function which goes through all permutations.

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