PHP Iterating Through Associative Array

Question

So I have the following, working code:

$arrayitertest=Array("Fruit"=>Array("Pear","Peach","Apple","Banana"),"Cars"=>Array("My budget","other cars."));

foreach ($arrayitertest as $key=>$value)
foreach($arrayitertest[$key] as $result) echo $key.":". $result."|";

But when I change foreach ($arrayitertest as $key => $value) to foreach ($arrayitertest as $key) it throws a fatal error (despite the fact I never use the $key variable.)

The Error is:Invalid argument supplied for foreach() in

Could someone be so kind as to tell me why that happens ?

Edit: Wow, thanks for all the answers.... I will give the accept to the most specific one as of this moment though.

Can you post the error? Also in the first foreach you have $key/$value vars backwards. — Mike Purcell
– Mike Purcell, Commented Mar 7, 2013 at 23:47
You have a bracket that isn't closed after the first foreach. — shapeshifter
– shapeshifter, Commented Mar 7, 2013 at 23:49
What @shapeshifter said. Your commenting out the closing bracket. Change //echo $value."|".$key1."\n"; to /*echo $value."|".$key1."\n";*/ to correctly comment out the code within the foreach. — Axel
– Axel, Commented Mar 7, 2013 at 23:51

jeroen · Accepted Answer · 2013-03-08 00:03:57Z

4

As far as your error is concerned: If you remove the $value from the first foreach, $key becomes the value and $arrayitertest[$key] becomes "pear" which is an invalid argument for the second foreach.

Your program would halt on:

// this is not going to work
foreach ("pear" as $result)

If you don't need the key of the first foreach you can just change it to:

foreach ($arrayitertest as $value)
{
   foreach($value as $result)
   {
   }
}

edited Mar 8, 2013 at 0:03

answered Mar 7, 2013 at 23:53

jeroen

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Comments

sh03 · Accepted Answer · 2013-03-07 23:52:59Z

3

I think you are misunderstanding the order of key and values. Where you say $value => $key it's technically $key => $value.

The way to parse your array is this:

foreach ($array as $key => $value) {
    foreach ($array[$key] as $v) {
        // $v = Pear (1st iteration), Peach (2nd), Apple (3rd) ... (for key = Fruit) 
        // $v = My Budget (1st iteration), other cars. (2nd) (for key = Cars)
        // notice that $key is also accessible here
    }
}

Obviously if you don't need the $key either you can simply:

foreach ($array as $a)
    foreach ($a as $v)
        // use $v here

answered Mar 7, 2013 at 23:52

sh03

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Comments

Captain Payalytic · Accepted Answer · 2013-03-07 23:55:12Z

0

Coding $value => $key, puts Fruit, Car, ... into $value.

Coding just $value puts the arrays such as Array("Pear","Peach","Apple","Banana") into $value and that is not a valid index for an array.

answered Mar 7, 2013 at 23:55

Captain Payalytic

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