[thelist] How to store data in multidimensional array in a loop (PHP)

[Phil Turmel]

Stefan Schwarzer wrote:
> Hi there,
> 
> I need to store three pieces of data - a result of a SQL query - in a  
> multidimensional array, but don't really succeed. Sometimes it works,  
> but then the output doesn't work accordingly.
> 
> My SQL result comes with something like this:
> Code: ( text )
> Africa   |    y2000   |   9430
> Africa   |    y2005   |   9678
> Europe   |    y2000   |   2314
> 
> where there are 6 regions and multiple years.
> 
> Last thing I came up with was this for stocking the data in the array:
> Code: ( php )
> $sum_pop_total_dataset[] = array($row['reg_name'] => array($row 
> ['year'], $row['popt']));
> 
> 
> That seemed to work. But then the output function went a bit wrong:
> Code: ( php )
> while (list($key1) = each ($sum_pop_total_dataset))
> {
>      echo "<br />key1: ".$key1;
>      while (list($key2, $value) = each ($sum_pop_total_dataset[$key1]))
>      {
>          echo "<br />key2: ".$key2."   value: ".$value[0];
> 
>      }
> }
> 
> 
> Code: ( html4strict )
> key1: 0
> key2: North America value: y_2005
> key1: 1
> key2: Europe value: y_2005
> key1: 2
> key2: Asia + Pacific value: y_2005
> 
> 
> So, it seemed that the allocation of the SQL result to the principal  
> variable didn't work correctly. But if I take the [] away from  
> $sum_pop_total_dataset[]*= ..., than the variable is being re- 
> initialized at each time.
> 
> Can someone give me a hint what I should do?
> 
> Thanks a lot!
> 
> Stef

Hi Stef,

You need to specify the keys you want to store inside the []s, like this:

$sum_pop_total_dataset[$row['reg_name']][$row['year']] = $row;

This also leaves the original key names, so you would use:

$value['year'] and $value['popt'] instead of $value[0] and $value[1].

HTH,

Phil