CODEWITHSUNDEEP
phpforeach
DataMiner
DataMiner

Reputation: 13

Nested Foreach() PHP

I need some assistance with my code logic: The expected output of the following code is 1110, how to achieve that value?

<?php 
        $user_accepted_events = [1,2,3];
        $all_events = [1,2,3,4]; 

          //Nested foreach loop for testing if the user accepted an event

          foreach ($all_events as $single_row) {
                foreach ($user_accepted_events as $user_single_id) {
                  if ($single_row == $user_single_id) { //This prints expected value
                      print_r("1"); //User has accepted event
                    } else { //Here it logically print's 0 nine times 
                      print_r("0"); //User has not accepted Event
                  }
                  }

                }


//Expected Output is 1110
//Real Output is 100010001000

?>

Thanks.

Upvotes: 1

Views: 59

Answers (2)

Martin
Martin

Reputation: 16453

You've got a logical error in your code: you are printing 1 or 0 for every permutation of both loops.

As there are 4 items in the outer loop and 3 in the inner, you are receiving 12 outputs.

Instead, keeping the same approach you have already adopted, you can capture whether the user has attended the event in a variable, and break if so.

Then once for each of the outer loops, output the result:

$user_accepted_events = [1,2,3];
$all_events = [1,2,3,4]; 

foreach ($all_events as $single_row) {
    $hasAccepted = false;

    foreach ($user_accepted_events as $user_single_id) {
        if ($single_row == $user_single_id) {
            $hasAccepted = true;
            break;
        }
    }

    print_r($hasAccepted ? 1 : 0);
}

Output:

1110

Upvotes: 1

Nigel Ren
Nigel Ren

Reputation: 57141

As you have nested loops - it will compare each item against every nested item and most of them won't match - producing multiple results for each item.

Instead - use in_array() to check each item...

foreach ($all_events as $single_row) {
    if ( in_array($single_row, $user_accepted_events))  {
        print_r("1"); //User has accepted event
    } else {
        print_r("0"); //User has not accepted Event
    }
}

Upvotes: 3

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