Add value to existing array key in foreach loop - php

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;
}

Answer 1

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']}";
}

Answer 2

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
)
)

Answer 3

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
)

Answer 4

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);

Answer 5

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']:'');
}

Answer 6

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.

Answer 7

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