Merging arrays within an array, preserving numeric index

Question

Array_merge and array_merge_recursive are not working as desired, creating more indexes instead of pushing the arrays together and retaining the index number. See below for input/desired output:

Array (
    [0] => array(
        [0] => "string1",
        [1] => "string2",
        [2] => "string3"
    ),
    [1] => array(
        [0] => "string4",
        [1] => "string5",
        [2] => "string6"
    ),
    [2] => array(
        [0] => "string7",
        [1] => "string8",
        [2] => "string9"
    )
)

Desired Output:

Array (
    [0] => array("string1","string4","string7"),
    [1] => array("string2","string5","string8"),
    [2] => array("string3","string6","string9")

)

EDIT:

Perhaps not the best example; I want to achieve the same results but with an unequal number of keys in each nested array. See below for a better example:

<?php
$array = Array (
[0] => array(
    [0] => "string1",
    [1] => "string2",
    [2] => "string3"
    ),
[1] => array(
    [0] => "string4",
    [1] => "string5",
    [2] => "string6"
    ),
[2] => array(
    [0] => "string7",
    [1] => "string8",
    [2] => "string9"
    ),
[3] => array(
    [0] => "string10",
    [1] => "string11",
    [2] => "string12"
    )
);

$output=array();
    for($0=0;$j<count($array[0]);$j++){
        $output[$j] = array();
    }

for($i=0;$i<count($array);$i++){
    for($0=0;$j<count($array[0]);$j++){
        $output[$j] = array_push($output[$j],$column_values[$i][$j]);
    }
}


?>

But when I do this, I get the correct number of keys in my $output array, but they all contain a bool(false). Any help?

This is the desired output:

Array (
    [0] => array("string1","string4","string7","string10"),
    [1] => array("string2","string5","string8","string11"),
    [2] => array("string3","string6","string9","string12")
)

I don't think merge is the right method here anyways. You want to restructure the whole array, so iterate over the elements and create a new array. — Felix Kling
– Felix Kling, Commented May 24, 2012 at 17:30

HamZa · Accepted Answer · 2012-05-24 18:50:04Z

1

This is to make an array just for this structure of array, so you may change the code depanding on your needs ...

<pre>
<?php
    $array = array(array("string1","string2","string3"),array("string4","string5","string6"),array("string7","string8","string9"));
    $output=array();
    for($i=0;$i<count($array[0]);$i++){
        for($j=0;$j<count($array[0]);$j++){
            $output[$i][$j] = $array[$j][$i];
        }
    }

    print_r($output);
?>
</pre>

answered May 24, 2012 at 18:50

HamZa

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1 Comment

user1174265 Over a year ago

This works great for this example, where there are the same number of keys in both input arrays, but what if there are more keys in the first array than the second?

HamZa · Accepted Answer · 2012-05-25 22:51:40Z

0

This is for your 'second' situation:

<?php

    $array = array(array("string1","string2","string3"),array("string4","string5","string6"),array("string7","string8","string9"),array("string10","string11","string12"));
    $output=array();

    for($i=0;$i<count($array[0]);$i++){
        for($j=0;$j<=count($array[0]);$j++){
            $output[$i][$j] = $array[$j][$i];
        }
    }
    print_r($output);
?>

answered May 25, 2012 at 22:51

HamZa

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Comments

Miroslav Bajtoš · Accepted Answer · 2012-05-27 00:16:26Z

0

Got it. Last loop should simply array_push($output[$j],$column_values[$i][$j]); instead of trying to set the variable $output[$j] = array_push(Yadda,yadda).

edited May 27, 2012 at 0:16

Miroslav Bajtoš

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answered May 25, 2012 at 19:25

user1174265

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