PHP foreach loops

Question

This is making me insane. I've validated my input/outputs, and I'm still getting unexpected behavior. It should be 2, but it's doing numa numa. What am I missing?

Input:

data
Array
(
    [0] => Array
        (
            [lineId] => 1
            [quantity] => 2
            [costPerItem] => 16.585
            [itemId] => 1
        )

)

Code:

printr( $data, 'data' );
foreach( $data as $i => $value ){
    foreach( $value as $key => $a ){
        echo 'key: '.$key.' - a: '.$a.'<br />';
        ( $key == 'quantity' ) ? $dataQuantity[$i] = $a : $dataQuantity[$i] = 'numanuma'; 
    }
}
printr( $dataQuantity, 'data quantity' );

Output:

key: lineId - a: 1
key: quantity - a: 2
key: costPerItem - a: 16.585
key: itemId - a: 1

data quantity
Array
(
    [0] => numanuma
)

I'm not breaking the foreach loop here, and I shouldn't have to. I skinnied the code down trying to debug it. — phpmeh
– phpmeh, Commented Feb 12, 2013 at 18:34

Niels · Accepted Answer · 2013-02-12 18:34:19Z

3

This is because the key itemId is after the quantity key. So it was set to 2 but the loop after it was set to numanuma.

Try this:

printr( $data, 'data' );
foreach( $data as $i => $value ){
    foreach( $value as $key => $a ){
        echo 'key: '.$key.' - a: '.$a.'<br />';
        if( $key == 'quantity' )
        { 
            $dataQuantity[$i] = $a; 
        } 
    }
}
printr( $dataQuantity, 'data quantity' );

answered Feb 12, 2013 at 18:34

Niels

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1 Comment

phpmeh Over a year ago

Wow, i added the ternary trying to debug, and that was a stupid mistake. Thanks.

Colin M · Accepted Answer · 2013-02-12 18:35:34Z

There are a couple of things wrong with this.

First, you're setting the value $dataQuantity[$i] in your sub-loop but $i is incremented in your outer loop.

When your code sees 'quantity' it may set $dataQuantity[$i] to 2, but then it sees itemId and overrides $dataQuantity[$i] since $i hasn't changed.

Secondly, you should change your ternary if statement to this:

$dataQuantity[$i] = ( $key == 'quantity' ) ? $a : 'numanuma';

That doesn't factor for what I mentioned previously.

Here's a working sample:

printr( $data, 'data' );
foreach( $data as $i => $value ){
    foreach( $value as $key => $a ){
        if ($key == 'quantity') {
            $dataQuantity[$i] = $a;
            break;
        }
    }
}
printr( $dataQuantity, 'data quantity' );

slugonamission · Accepted Answer · 2013-02-12 18:34:13Z

2

You assign "numanuma" if the key is not "quantity". After the "quantity" key, some keys are not quantity, so "numanuma" is assigned over the value of $a.

Short answer, add an extra check and a flag to check if $dataQuantity[$i] has already been assigned correctly before assigning "numanuma".

answered Feb 12, 2013 at 18:34

slugonamission

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Comments

user1646111 · Accepted Answer · 2013-02-12 18:35:24Z

0

Ternary operator not used for assigning value please read this:

Note: Please note that the ternary operator is a statement, and that it doesn't evaluate to a variable, but to the result of a statement. This is important to know if you want to return a variable by reference. The statement return $var == 42 ? $a : $b; in a return-by-reference function will therefore not work and a warning is issued in later PHP versions.

Source

answered Feb 12, 2013 at 18:35

user1646111

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