[Phpwm] updating an array

[alan dunn]

We made it!! Thanks to everyone who helped - it has taken me 3 days to 
get there, but without the group we would still be totally lost.
The final code is quite terse, after wrestling with duplicated arrays, 
for_each loops et al,  if you care here it is:

Again thank you all for your support.

else
        {
            if(array_key_exists($e1, $prodarray))
            {
                $prodarray[$e1] += $q1;
            }
            // if product does not exist in array - add it
            else{$prodarray[$e1] = $q1;}
           
            // now deal with e2
            if(!empty($e2))
            {
                if(array_key_exists($e2, $prodarray))
                {
                    $prodarray[$e2] += $q2;
                }
                // if product does not exist in array - add it
                else{$prodarray[$e2] = $q2;}
            }
            // now deal with e3
            if(!empty($e3))
            {
                if(array_key_exists($e3, $prodarray))
                {
                    $prodarray[$e3] += $q3;
                }
                // if product does not exist in array - add it
                else{$prodarray[$e3] = $q3;}
            }
            // now deal with e4
            if(!empty($e4))
            {
                if(array_key_exists($e4, $prodarray))
                {
                    $prodarray[$e4] += $q4;
                }
                // if product does not exist in array - add it
                else{$prodarray[$e4] = $q4;}
            }
        } // end else

David Long wrote:
> alan dunn wrote:
>> here is my prodarray after the first iteration:
>>
>> Array ( [8x6_blue] => 2 [7x5_blue] => 4 [3x2_and_pass] => 4 [jobcard] 
>> => 2 )
>>
>> then my next line has quantity 3 of 8x6_blue
>>
>> now I want to say if 8x6_blue is in_array prodarray (as a key value) 
>> add 3 to 2
>>
>> but in_array is saying does 8x6_blue equal '2' or '4' or '4' or '2'
>> which of course it doesn't
>
> You need array_key_exists instead of in_array for this:
>
>    // loop through second array
>    foreach ($secondarray as $key => $qty)
>    {
>        if(array_key_exists($key, $prodarray))
>        {
>            $prodarray[$key] += $qty;
>        }
>        else
>        {
>            $prodarray[$key] = $qty;
>        }
>    }
>
> You could also use isset($prodarray[$key]) in this situation, but in 
> cases where null values are used in the array it doesn't quite work as 
> you expect (see the isset documentation for more details).
>
> If you don't care about PHP warnings, non-existent array keys return 
> NULL, which are converted to 0 if you treat them as an integer, so you 
> don't even need to do the test:
>
>    // loop through second array
>    foreach ($secondarray as $key => $qty)
>    {
>        $prodarray[$key] += $qty;
>    }
>
> Dave
>
>
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