Variables defined within a loop are not defined outside the loop (PHP)

Question

I have a series of variables, I want to check if they are 0 or not, and if they are, I wish to redefine the variable to equal the string 'Unavailable'.

To do this I wrote a loop:

$indicators=array($admitted, $targeted, $cured, $defaulted, $total);

foreach($indicators as $indicator)
{   
if($indicator==0)
    {
    $indicator='Unavailable';
    }       
}

This checks to see if each of the variables in the array $indicators is equal to zero, and if so redefines it.

However, after this loop is closed a table is built using the variables:

$table1 .= '
            <tr>
                    <td>'.$year.'</td>
                    <td>'.$targeted.'</td>
                    <td>'.$admitted.'</td>
                    <td>'.$total.'</td>
                    <td>'.$cured.'</td>
                    <td>'.$defaulted.'</td>                 
            </tr>
            ';

The output of which includes some '0' terms - they are never substituted for the string 'Unavailable'.

I debugged the code with the following:

foreach($indicators as $indicator)
{
echo 'Before: '.$indicator;
if($indicator==0)
    {
    $indicator='Unavailable';
    }
    echo '<br />';
echo 'After :'.$indicator;
}

And confirmed that it was redefining the variables, but that redefiniton was not applying outside of the loop.

I feel this is an issue with scope - which I confess to not understanding well.

My question is: how can I get the variables defined inside a loop to apply outside of that loop?

Many thanks for your thoughts.

Mark Parnell · Accepted Answer · 2013-03-22 04:09:44Z

3

That's because all you're doing is updating the variable $indicator, not the original elements of the array.

There are 2 ways of doing this. Either pass by reference:

foreach($indicators as &$indicator)

or manually push the change back to the array:

foreach($indicators as $idx => $indicator)
{   
    if($indicator==0)
    {
        $indicators[$idx]='Unavailable';
    }       
}

answered Mar 22, 2013 at 4:09

Mark Parnell

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1 Comment

Gideon Over a year ago

Thanks, didn't know about pass by reference before!

alwaysLearn · Accepted Answer · 2013-03-22 04:21:38Z

0

You are not assigning the changed value back to array

try this

foreach($indicators as $key=>$indicator)
{   
 if($indicator==0)
   {
  $indicator[$key]='Unavailable';
  }       
}

answered Mar 22, 2013 at 4:21

alwaysLearn

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