Group values in multi-dimensional array based on a key-CodePudding

I have the following multi-dimensional array:

Array
(
    [0] => Array
        (
        [sname] => florida
        [cname] => orlando
        )

    [1] => Array
        (
        [sname] => texas
        [cname] => dallas
        )

    [2] => Array
        (
        [sname] => florida
        [cname] => tampa
        )

    [3] => Array
        (
        [sname] => ohio
        [cname] => columbus
        )

)

How would I go about trying to get all 'cname' values associated with each 'sname' value?

florida:    orlando, tampa
texas:      dallas
ohio:       columbus

CodePudding user response：

With a slight tweak of Mike's solution (https://stackoverflow.com/a/2189916/4954574), the following will produce what I was hoping for:

$input_arr = array(
    array("sname" => "florida", "cname" => "orlando"),
    array("sname" => "texas", "cname" => "dallas"),
    array("sname" => "florida", "cname" => "tampa"),
    array("sname" => "ohio", "cname" => "columbus")
);

foreach ($input_arr as $key => &$entry) {
    $level_arr[$entry['sname']][$key] = $entry['cname'];
}

print_r($level_arr);

Output:

Array
(
    [florida] => Array
        (
            [0] => orlando
            [2] => tampa
        )

    [texas] => Array
        (
            [1] => dallas
        )

    [ohio] => Array
        (
            [3] => columbus
        )

)

I am new with PHP arrays, so I'm not certain if this is the most efficient way or not?

CodePudding user response：

There are probably several ways to do this. The one that comes to mind is something like this:

<?php

$payload = [];
$origin = [
    [
        'sname' => 'florida',
        'cname' => 'orlando'
    ],
    [
        'sname' => 'texas',
        'cname' => 'dallas'
    ],
    [
        'sname' => 'florida',
        'cname' => 'tampa'
    ],
    [
        'sname' => 'ohio',
        'cname' => 'columbus'
    ]
];


foreach ($origin as $value) {
  if (! isset($payload[$value['sname']])) {
    $payload[$value['sname']] = '';
  }

  $payload[$value['sname']] .= (strlen($payload[$value['sname']]) >0?',':'') . $value['cname'];
}

print_r($payload);

Cheers! :)

=C=