Function to Flip Array Values to Array Keys?

Question

Is there a php function which can take the below array

array (size=4)
 1 => string '0' 
 6 => string '1' 
 7 => string '1' 
 8 => string '7'

And flip it to the below array notice that an array must have unique key values so can we flip the array where value 1 = key values 6, 7

array (size=3)
 0 => string '1' 
 1 => string '6, 7'
 7 => string '8'

@splash58 not quite. `array_flip` won't concatenate keys that have the same value.. — Ankh, Jun 11 '15 at 15:00
There is no such function, you'll need to write it yourself. Good Luck! — Daan, Jun 11 '15 at 15:00
If you just searched same question title on google you will see php manual for array_flip function — Mohamed Belal, Jun 11 '15 at 15:38

splash58 · Accepted Answer · 2015-06-11T15:34:03.203

11

$arr = array ( 1 => '0', 6 => '1', 7 => '1', 8 => '7' );

// Find unique values of array and make them as keys
$res = array_flip($arr);
// Find keys from sourse array with value of key in new array
foreach($res as $k =>$v) $res[$k] = implode(", ", array_keys($arr, $k));

result

Array
(
    [0] => 1
    [1] => 6, 7
    [7] => 8
)

edited Jun 11 '15 at 15:34

answered Jun 11 '15 at 15:21

splash58

26,043
3
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Nice little explanation and nice use of `array_keys()` with `implode()`. – Rizier123 Jun 11 '15 at 15:30
@Rizier123 Even a cat likes a kind word :) – splash58 Jun 11 '15 at 15:36
@Rizier123 What you say about [this answer](http://stackoverflow.com/a/30795697/2899618) – Narendrasingh Sisodia Jun 12 '15 at 05:13

score 4 · Answer 2 · answered Jun 12 '15 at 05:13

4

You can try it as

Simply use foreach and interchange the values of key with values

$arr = array ( 1 => '0', 6 => '1', 7 => '1', 8 => '7' );
$result = array();
foreach($arr as $key => $value){
    $result[$value][] = $key;
}
print_r($result);

FIDDLE

answered Jun 12 '15 at 05:13

Narendrasingh Sisodia

21,247
6
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score 3 · Answer 3 · answered Jun 11 '15 at 15:17

No, there is not an existing, but you can write your's custom as per need, see the below function does exact what you need:

function customFlip($arr){
    $newArray = array();
    if (is_array($arr)) {
        foreach ($arr as $key => $value) {
            if (array_key_exists($value, $newArray)) {
                if (empty($newArray[$value])) {
                    $newArray[$value] = $key;
                } else {
                    $newArray[$value] .= ','.$key;
                }
            } else {
                $newArray[$value] = $key;
            }
        }
        return $newArray;
    }
    return false;
}

There is a function called array_flip – Mohamed Belal Jun 11 '15 at 15:36 — Mohamed Belal, Jun 11 '15 at 15:36

Function to Flip Array Values to Array Keys?

3 Answers3

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