Add value to existing array key in foreach loop

Question

I have the following bibliography data in an array (note that fields are in random order - there are others fields as well):

Array
(
    [0] => Array
        (
            ['Pub_Name'] => Nature
            ['Volume'] => 6
            ['Pages'] => 215-217
        )
    [1] => Array
        (
            ['Volume'] => 15
            ['Pages'] => 358-360
            ['Pub_Name'] => Science            
        )
    [2] => Array
        (
            ['Pub_Name'] => PNAS
            ['Pages'] => 17-19            
            ['Volume'] => 22
        )
)

I want to "merge" those three fields into one, for example ['Pub_Name']=Nature, 6: 215-217. I tried the following whitout success (I guess $Record['Pub_Name'] is the incorrect sintax):

foreach ($MyArray as $Record) {
    foreach ($Record as $key => $values) {
        if ($key=="Volume") {$Volumen=", ".$values;} else {$Volumen="";}
        if ($key=="Pages") {$Paginas=": ".$values;} else {$Paginas="";}
    }

    //This is the line for which I want to know the sintax!!
    $Record['Pub_Name'].=$Volumen.$Paginas;
}

Check out php.net/manual/en/function.array-values.php

Matt
– Matt

2017-04-04 15:51:32 +00:00
Commented Apr 4, 2017 at 15:51 — Matt
– Matt, Commented Apr 4, 2017 at 15:51

AbraCadaver · Accepted Answer · 2017-04-04 15:54:06Z

2

No need for two loops:

foreach ($MyArray as $Record) {
    $result[]['Pub_Name'] = "{$Record['Pub_Name']}, {$Record['Pages']}: {$Record['Volume']}";
}

Then you have the new Pub_Name entries in $result.

If you want to modify the original then reference & $Record:

foreach ($MyArray as &$Record) {
    $Record['Pub_Name'] = "{$Record['Pub_Name']}, {$Record['Pages']}: {$Record['Volume']}";
}

Or use the key and modify the original array:

foreach ($MyArray as $key => $Record) {
    $MyArray[$key]['Pub_Name'] = "{$Record['Pub_Name']}, {$Record['Pages']}: {$Record['Volume']}";
}

answered Apr 4, 2017 at 15:54

AbraCadaver

79.2k7 gold badges75 silver badges91 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

CMArg Over a year ago

It worked, thanks! And please, what does & account for in your second option?

AbraCadaver Over a year ago

It's a reference that modifies the array when you modify $Record. Explained here: php.net/manual/en/control-structures.foreach.php

CMArg Over a year ago

thanks. The warning for unseting $Record of your link also helped me...

Sahil Gulati · Accepted Answer · 2017-04-04 16:04:59Z

PHP code demo

<?php
$array=Array
(
    0 => Array
        (
            'Pub_Name' => "Nature",
            'Volume' => 6,
            'Pages' => "215-217"
        ),
    1 => Array
        (
            'Volume' => 15,
            'Pages' => "358-360",
            'Pub_Name' => "Science"            
        ),
    2 => Array
        (
            'Pub_Name' => 'PNAS',
            'Pages' => "17-19",          
            'Volume' => 22
        )
);
$result=array();
foreach ($array as $data)
{
    $result[]=array('Pub_Name'=>  $data['Pub_Name'].", ".$data["Volume"].": ".$data["Pages"]);

}
print_r($result);

Output:

Array
(
    [0] => Array
        (
            [Pub_Name] => Nature, 6: 215-217
        )

    [1] => Array
        (
            [Pub_Name] => Science, 15: 358-360
        )

    [2] => Array
        (
            [Pub_Name] => PNAS, 22: 17-19
        )

)

arkascha · Accepted Answer · 2017-04-04 15:56:44Z

0

I guess this is what you are looking for:

<?php
$input = [
    [
        'Pub_Name' => 'Nature',
        'Volume' => '6',
        'Pages' => '215-217'
    ],
    [
        'Volume' => '15',
        'Pages' => '358-30',
        'Pub_Name' => 'Science',
    ],
    [
        'Pub_Name' => 'PNAS',
        'Pages' => '17-19',
        'Volume' => '22'
    ]
];
$output = [];
array_walk($input, function ($entry) use (&$output) {
    $output[] = sprintf(
        '%s, %s: %s',
        $entry['Pub_Name'],
        $entry['Volume'],
        $entry['Pages']
    );
});
print_r($output);

The output of above code obviously is:

Array
(
    [0] => Nature, 6: 215-217
    [1] => Science, 15: 358-30
    [2] => PNAS, 22: 17-19
)

answered Apr 4, 2017 at 15:56

arkascha

43.2k8 gold badges61 silver badges97 bronze badges

Comments

ponury-kostek · Accepted Answer · 2017-04-04 15:59:51Z

0

Use array_map

$in = [
    0 => [
        'Pub_Name' => 'Nature',
        'Volume' => 6,
        'Pages' => '215-217'
    ],
    1 => [
        'Volume' => 15,
        'Pages' => '358-360',
        'Pub_Name' => 'Science',
    ],
    2 => [
        'Pub_Name' => 'PNAS',
        'Pages' => '17-19',
        'Volume' => 22
    ]
];

array_map(function ($item) {
    return $item['Pub_Name'] . ', ' . $item['Volume'] . ': ' . $item['Pages'];
}, $in);

answered Apr 4, 2017 at 15:59

ponury-kostek

8,0835 gold badges27 silver badges33 bronze badges

Comments

Anthony Gray · Accepted Answer · 2017-04-04 16:03:53Z

0

There are a few different ways to do this - but one of the more readable ways:

// create a copy of the original - so we aren't looping thru the same array we're updating
$updatedArray = $MyArray;

foreach ($MyArray as $index => $record) {
    $updatedArray[$index]['Pub_Name'] =
        $record['Pub_Name'].  
        ($record['Volume'] ? ', '.$record['Volume'] : ''). 
        ($record['Pages'] ? ': '.$record['Pages']:'');
}

answered Apr 4, 2017 at 16:03

Anthony Gray

3944 silver badges7 bronze badges

Comments

MarcM · Accepted Answer · 2017-04-04 16:18:22Z

0

Clear way in a single loop. Use sprintf() for easy formatting:

<?php
$src =[ ['Pub_Name' => 'Nature', 'Volume' => '6', 'Pages' => '215-217'],
        ['Volume' => '15', 'Pages' => '358-30', 'Pub_Name' => 'Science'],
        ['Pub_Name' => 'PNAS', 'Pages' => '17-19',  'Volume' => '22']
      ];

foreach ($src as $element) {
    $dest[] = sprintf("%s, %d: %s", 
       $element['Pub_Name'], 
       $element['Volume'], 
       $element['Pages']);
}

var_dump($dest);
?>

And you get:

    array(3) { 
[0]=> string(18) "Nature, 6: 215-217" 
[1]=> string(19) "Science, 15: 358-30" 
[2]=> string(15) "PNAS, 22: 17-19"
 }

Test it here.

edited Apr 4, 2017 at 16:18

answered Apr 4, 2017 at 16:11

MarcM

2,2511 gold badge25 silver badges32 bronze badges

1 Comment

CMArg Over a year ago

Thanks a lot. So many answers in minutes (I've been stuck with this for a long time). Sadly there can be only one accepted answer.

FrenchMajesty · Accepted Answer · 2017-04-05 18:16:53Z

-1

This should help:

$combined = [];
foreach($myArray as $pub) {
    $combined.push($pub['Pub_Name'] . ', ' . $pub['Volume'] . ': ' . $pub['Pages']);
}

edited Apr 5, 2017 at 18:16

answered Apr 4, 2017 at 15:57

FrenchMajesty

1,1492 gold badges16 silver badges30 bronze badges

Collectives™ on Stack Overflow

Add value to existing array key in foreach loop

7 Answers 7

3 Comments

Comments

Comments

Comments

Comments

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

7 Answers 7

3 Comments

Comments

Comments

Comments

Comments

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related