split php array by value - php

Question

I have this array
array
0 =>
array
'prodid' => string '2' (length=1)
'qty' => int 2
'price' => string '100.00' (length=6)
'sid' => string '13' (length=2)
2 =>
array
'prodid' => string '3' (length=1)
'qty' => int 1
'price' => string '380.00' (length=6)
'sid' => string '13' (length=2)
1 =>
array
'prodid' => string '8' (length=1)
'qty' => int 1
'price' => string '300.00' (length=6)
'sid' => string '24' (length=2)
How can i split it in to a multi dimentional array where the values 'sid' match like so.
array
0 =>
array
0 =>
array
'prodid' => string '2' (length=1)
'qty' => int 2
'price' => string '100.00' (length=6)
'sid' => string '13' (length=2)
1 =>
array
'prodid' => string '2' (length=1)
'qty' => int 2
'price' => string '100.00' (length=6)
'sid' => string '13' (length=2)
1 =>
array
0 =>
array
'prodid' => string '7' (length=1)
'qty' => int 1
'price' => string '200.00' (length=6)
'sid' => string '15' (length=2)

Answer 1

You pick the value you want to group with as key for a new array and push the member to it
$new = array();
foreach($array as $member)
{
$key = $member['group-value'];
$new[$key][] = $member;
}
You then extract the bare values from the new array by using array_values:
$new = array_values($new);
And that's it. If you want to spare the last part, you can also create the mapping of keys and it's numerical index on your own:
$new = array();
$keys = array();
foreach($array as $member)
{
$key = $member['group-value'];
isset($keys[$key]) || $keys[$key] = count($keys);
$new[$keys[$key]][] = $member;
}

Answer 2

For PHP5.3+
$result = array_reduce (
$array,
function ($item, $result) {
if (!isset($result[$item['sid']])) $result[$item['sid']] = array();
$result[$item['sid']][] = $item;
return $result;
},
array()
)

Answer 3

// $ouput array will be indexed by the 'sid' value
$output = array();
// Iterate over the main array and create a new subarray if
// it doesn't already exist, or add to it if it does.
foreach($input as $subarr) {
if (!isset($output[$subarr['sid']]) {
// New array indexed by sid
$output[$subarr['sid']] = array();
}
// Append the whole array
$output[$subarr['sid']][] = $subarr;
}
Note: this produces slightly different output than you described, in that it uses the sid as array keys rather than just indexing them from 0:
array
// Note key difference...
// sid == 13
13 =>
array
0 =>
array
'prodid' => string '2' (length=1)
'qty' => int 2
'price' => string '100.00' (length=6)
'sid' => string '13' (length=2)
1 =>
array
'prodid' => string '2' (length=1)
'qty' => int 2
'price' => string '100.00' (length=6)
'sid' => string '13' (length=2)
// sid == 15
15 =>
array
0 =>
array
'prodid' => string '7' (length=1)
'qty' => int 1
'price' => string '200.00' (length=6)
'sid' => string '15' (length=2)