php recursive function doesn't work

Question

I have a problem to understand why this doesn't work. I have recursive function who check if value in multidimensional array exists. Then I have get_teams() function from which I want to return only unique values. I check for unique values with my find_value() function but it still return all the values.. Can someone explain me what happens? Thanks in advance

function find_value( $array, $searched_val ) {
    foreach ( $array as $key => $val ) {
        if ( $val === $searched_val ) {
            return true;
        }

        if ( is_array( $val ) ) {
            return find_value( $val, $searched_val );
        }
    }
    return 0;
}

get_teams();

function get_teams() {
    $people = get_data( 'some/file.json' );
    $teams = [];

    foreach ( $people as $person ) {
        if (  ! find_value( $teams, $person['team'] ) ) {
            $teams[] = [ 'text' => $person['team'] ];
        }
    }
    return $teams;
}

This is sample input

Array
(
[0] => Array
    (
        [id] => 1
        [name] => Friedrich Robel
        [team] => WordPress
        [position] => Frontend Developer
        [salary] => 4400
    )

[1] => Array
    (
        [id] => 2
        [name] => Mr. Christop Veum
        [team] => HTML
        [position] => Manager
        [salary] => 1200
    )

[2] => Array
    (
        [id] => 3
        [name] => Demarco Rippin
        [team] => HTML
        [position] => QA
        [salary] => 4400
    )

[3] => Array
    (
        [id] => 4
        [name] => Felicia Farrell
        [team] => HTML
        [position] => QA
        [salary] => 1200
    )

[4] => Array
    (
        [id] => 5
        [name] => Torrance Fritsch
        [team] => HTML
        [position] => Assistant Manager
        [salary] => 2500
    )

[5] => Array
    (
        [id] => 6
        [name] => Erica Daugherty
        [team] => Mail
        [position] => Assistant Manager
        [salary] => 500
    )
)

And I want this output

 Array
(
[0] => WordPress,
[1] => HTML,
[2] => Mail
)

We'd need ssample input and your desired output in order to tell you the problem. — Jay Blanchard
– Jay Blanchard, Commented Mar 5, 2018 at 22:05

Syscall · Accepted Answer · 2018-03-05 22:17:31Z

2

Your problem is that you returns the result of the sub-search without testing it.

Instead of return find_value(...), you have to test its value.

function find_value( $array, $searched_val ) {
    foreach ( $array as $key => $val ) {
        if ( $val === $searched_val ) {
            return true;
        }

        if ( is_array( $val ) ) {

            // Here, you have to test the result before to return TRUE.
            if (find_value( $val, $searched_val )) {
                return true ;
            }
        }
    }
    return 0;
}

answered Mar 5, 2018 at 22:17

Syscall

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Comments

sorak · Accepted Answer · 2018-03-06 05:09:47Z

The fix is, as Syscall posted, to test the return of find_value(), and only return if it is true.

As your code is structured now, it will return either true or false from the recursion call, which will always be required, since you are storing your values as [ 'text' => $person['team'] ];

The way your code is designed, with the return 0 outside the foreach is only to return false in the case a match was not found. For this reason, returning a false from the contents of that conditional is premature. Your loop does not have a chance to iterate and test all the values of the passed array. This early returning results in duplicate array entries.

In any case, the results at the end will be an array of ['text' => '<job>'] array members. If you want only the job string, assign like this instead:

$teams[] = $person['team'];

If you make this change, the other is not required. Note that it also removes the need for recursion, as $teams will contain only an array of strings.

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