PHP - Updating arrays within arrays using foreach

smcelhinney · 12-05-2011 12:05AM #1

Hey guys.

Ok, been googling for a little while now, but Im having no joy. Consider the following pseudo code.

$a = array();
$b = array("foo" => "bar", "blah" => "two", "what" => "yeah");
$a[] = $b; 

// so far so good.. however

foreach($a as $x){
   // First array item is obviously $b
   if($someBoolean){
     $x['hasValue'] = true;
   }
}

But $b is never updated with the new element.

Any thoughts?

Goodshape · 12-05-2011 01:38AM

Array's aren't persistent like that. When you foreach $a as $x, $x is a new thing... it has the properties of $b but it isn't $b. Also, on the next iteration of the loop it's going to be re-written anyway ($x is set for each value in $a). Changes you make to $x do not carry back.

Depending on your script though, you should be able to rework it. For your psudo-code, something like:

[php]
$a = array();
$b = array("foo" => "bar", "blah" => "two", "what" => "yeah");
$a[] = $b; // so now $a[0] is $b;

$i = 0;
foreach($a as $x)
{
if($someBoolean)
{
$a[$i] = true; // now we're changing the $a[0] variable, not the $x.
}
$i++;
}
[/php]

ocallagh · 12-05-2011 12:18PM

or if the array is associative you don't need the counter

[PHP]foreach($array as $key=>$value)
{
$array[$key] = $newvalue;
}[/PHP]

komodosp · 12-05-2011 03:46PM

I believe you can update it using a reference to the element... i.e.

foreach ($array as &$element) {
 $element = $new_value;
}

Liam Byrne · 12-05-2011 05:28PM

foreach ($array as $k=>$v) {
   $array[$k]=$newValue;
}

Skiex · 17-05-2011 11:50AM

Your using a hasValue.

Are you just checking if a variable is in an array?

Whats the goal?

PHP - Updating arrays within arrays using foreach

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