php - how to merge 2d array that have different no of element for each array

Question

I have 2 set of 2d array and i want merge into 1 2d array. but the number of element in each array its not same and for the first 2 element is same and i don't want to duplicate it. here its is.

First 2d array:

Array(   
       [0] => Array
           (
              [0] => 25/2/2013
              [1] => 8.45 a.m
              [2] => 9.98
           )

       [1] => Array
           (
              [0] => 25/2/2013
              [1] => 8.46 a.m
              [2] => 9.02
           )
     )

second 2d array:

 Array(   
        [0] => Array
            (
                [0] => 25/2/2013
                [1] => 8.45 a.m
                [2] => 1.23
                [3] => 6.1
            )

        [1] => Array
            (
                [0] => 25/2/2013
                [1] => 8.46 a.m
                [2] => 1.75
                [3] => 1.75
            )
      )

How do i get result as this:

Array(   
        [0] => Array
            (
                [0] => 25/2/2013
                [1] => 8.45 a.m
                [2] => 9.98
                [3] => 1.23
                [4] => 6.1
            )

        [1] => Array
            (
                [0] => 25/2/2013
                [1] => 8.46 a.m
                [2] => 9.02
                [3] => 1.75
                [4] => 1.75
            )
     )

here is var export for first array:

( 0 => array ( 0 => '5/2/2013', 1 => '9:31:00 AM', 2 => '0.395', 3 => '0.395', 4 => '302.855', 5 => '0.563', ), 1 => array ( 0 => '5/2/2013', 1 => '9:33:00 AM', 2 => '0.383', 3 => '0.383', 4 => '303.431', 5 => '0.563', )

and for second array:

( 0 => array ( 0 => '5/2/2013', 1 => '9:31:00 AM', 2 => '-1.000', 3 => '-1.000', 4 => '-1.000', 5 => '-1.670', 6 => '-1.000', 7 => '-11.000', ), 1 => array ( 0 => '5/2/2013', 1 => '9:33:00 AM', 2 => '-1.000', 3 => '-1.000', 4 => '-1.000', 5 => '-1.670', 6 => '-1.000', 7 => '-11.000', )

Ja͢ck · Accepted Answer · 2013-07-19 08:33:15Z

2

If both arrays are in the same order, the code is pretty straightforward:

$a = array(
    array('5/2/2013', '9:31:00 AM', '0.395', '0.395', '302.855', '0.563'),
    array('5/2/2013', '9:33:00 AM', '0.383', '0.383', '303.431', '0.563'),
);

$b = array(
    array('5/2/2013', '9:31:00 AM', '-1.000', '-1.000', '-1.000', '-1.670', '-1.000', '-11.000'),
    array('5/2/2013', '9:33:00 AM', '-1.000', '-1.000', '-1.000', '-1.670', '-1.000', '-11.000'),
);


$i = new MultipleIterator(MultipleIterator::MIT_NEED_ALL | MultipleIterator::MIT_KEYS_ASSOC);
$i->attachIterator(new ArrayIterator($a), 'a');
$i->attachIterator(new ArrayIterator($b), 'b');

$result = [];
foreach ($i as $v) {
    $result[] = array_merge($v['a'], array_slice($v['b'], 2));
}
print_r($result);

You basically iterate over both arrays at the same time and for each element construct the final array by merging the first with the second (skipping the common part).

Result:

Array
(
    [0] => Array
        (
            [0] => 5/2/2013
            [1] => 9:31:00 AM
            [2] => 0.395
            [3] => 0.395
            [4] => 302.855
            [5] => 0.563
            [6] => -1.000
            [7] => -1.000
            [8] => -1.000
            [9] => -1.670
            [10] => -1.000
            [11] => -11.000
        )

    [1] => Array
        (
            [0] => 5/2/2013
            [1] => 9:33:00 AM
            [2] => 0.383
            [3] => 0.383
            [4] => 303.431
            [5] => 0.563
            [6] => -1.000
            [7] => -1.000
            [8] => -1.000
            [9] => -1.670
            [10] => -1.000
            [11] => -11.000
        )
)

edited Jul 19, 2013 at 8:33

answered Jul 19, 2013 at 7:34

Ja͢ck

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4 Comments

zira Over a year ago

Hi @Jack, i got error when implement your code. array_slice() expect parameter 1 to be array, null given.

Ja͢ck Over a year ago

@zira Then that means your two arrays are not of equal size? Could you pastebin a var_export() of both arrays you tested with?

zira Over a year ago

yes, the size of two arrays not same.i have paste the output var export for both array that i'm tested above.

Ja͢ck Over a year ago

@zira I've tried those arrays and it doesn't give any warnings. Are you sure those are the correct ones?

DevZer0 · Accepted Answer · 2013-07-19 03:11:33Z

2

use array_merge_recursive example

$array = array_merge_recursive($array1, $array2);
 var_dump($array);

answered Jul 19, 2013 at 3:11

DevZer0

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3 Comments

ramiromd Over a year ago

If the @DevZer0 tip, dont work, yo can try do the merge yourself.

zira Over a year ago

Hi @DevZer0, i have tried but its not like what i want.because if i'm using array_merge_recursive, its only merge my two array respectively. i need it merging without duplicate the first two element which are date and time.

DevZer0 Over a year ago

@Zira you can use a custom array merge function then, can you update your post with the two arrays in a format i can copy and paste to code.

traq · Accepted Answer · 2013-07-19 04:16:46Z

It depends a lot on what your actual goal is. For instance, from your example, it seems that you want to use the date [index 0] (and possibly the time [index 1]) as a "primary key" of sorts, to control how data is merged.

There is no suitable function for this built in to PHP (as you've noticed, array_merge_recursive doesn't do what you want): you'll have to roll your own. There are a lot of "edge cases" to consider.

<?php
/**
 * recursively merges each item in $a1 and $a2 if their indexes [0] and [1] match;
 * appends the $a2 item instead if no matching item is found in $a1.
 *
 * @param  array  $a1 the first array to merge
 * @param  array  $a2 the second array to merge
 * @return array  the merged array
 */
function key_01_merge( array $a1,array $a2 ){
    // loop through each item in $a2
    foreach( $a2 as $a2_item ){
        // make sure it's an array with [0] and [1]
        if(
            ! is_array( $a2_item )
            || empty( $a2_item[0] )
            || empty( $a2_item[1] )
        ){
            // invalid; skip it
            break;
        }
        // compare it to each item in $a1; checking for matching "keys"
        foreach( $a1 as $a1_key => $a1_item ){
            if( 
                ! empty( $a1_item[0] )
                && ! empty( $a1_item[1] )
                && $a1_item[0] === $a2_item[0] 
                && $a1_item[1] === $a2_item[1] 
            ){
                // merge the two arrays
                // filter duplicate values
                // assign resulting array to the original index in $a1
                $a1[$a1_key] = array_unique( 
                    array_merge_recursive( $a1_item,$a2_item )
                );
                // set this item as "false" so it won't be appended to $a1
                $a2_item = false;
                // stop; continue with next item in $a2
                break;
            }
        }
        // if $a2_item was merged, it is now false;
        // otherwise, append it to the $a1 array
        if( $a2_item ){
            $a1[] = $a2_item;
        }
    }
    // return the $a1 array
    return $a1;
}

tested.

$a1 = [
    0 => [
        0 => '25/2/2013'
       ,1 => '8.45 a.m'
       ,2 => '9.98'
    ]
   ,1 => [
        0 => '25/2/2013'
       ,1 => '8.46 a.m'
       ,2 => '9.02'
    ]
];
$a2 = [   
    0 => [
        0 => '25/2/2013'
       ,1 => '8.45 a.m'
       ,2 => '1.23'
       ,3 => '6.1'
    ]
   ,1 => [
        0 => '25/2/2013'
       ,1 => '8.46 a.m'
       ,2 => '1.75'
       ,3 => '3.5'
    ]
];

var_dump( key_01_merge( $a1,$a2 ) );

outputs:

/*
array(2) {
  [0]=>
  array(5) {
    [0]=>
    string(9) "25/2/2013"
    [1]=>
    string(8) "8.45 a.m"
    [2]=>
    string(4) "9.98"
    [5]=>
    string(4) "1.23"
    [6]=>
    string(3) "6.1"
  }
  [1]=>
  array(5) {
    [0]=>
    string(9) "25/2/2013"
    [1]=>
    string(8) "8.46 a.m"
    [2]=>
    string(4) "9.02"
    [5]=>
    string(4) "1.75"
    [6]=>
    string(3) "3.5"
  }
}
*/

tq @traq .its work.but, how if i have same value for third and fourth element in $a2. 2=>'1.75', 3=>'1.75'.the output only show fourth element in new array.i have tried remove array_unique,but does not work. fyi, i only want to date and time not duplicate.other element remain after merging.

Expedito · Accepted Answer · 2013-07-19 11:19:34Z

0

$out = array();
for ($i=0; $i<count($arr1); $i++){
    $out[] = array_values(array_unique(array_merge($arr1[$i], $arr2[$i])));
}
var_dump($out);

Output:

Array
(
    [0] => Array
        (
            [0] => 25/2/2013
            [1] => 8.45 a.m
            [2] => 9.98
            [3] => 1.23
            [4] => 6.1
        )

    [1] => Array
        (
            [0] => 25/2/2013
            [1] => 8.46 a.m
            [2] => 9.02
            [3] => 1.75
        )

)

answered Jul 19, 2013 at 11:19

Expedito

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