accessing multidimensional array

Question

I am having some problems accessing some array data effectively and need a couple of tips.

I am doing a database call that returns data similar to this:

+------+------------+------------+-----------+
| id   | key        | part_num   |    value  |
+------+------------+------------+-----------+
|    1 | application| p1         |          1|
|    2 | application| p1         |          2|
|    3 | capsule    | p1         |          3|
|    3 | capsule    | p1         |          4|
|    4 | instrument | p1         |          5|
|    5 | instrument | p1         |          6|
|    5 | instrument | p1         |          7|
|    1 | application| n8         |          1|
|    2 | application| n8         |          2|
|    3 | capsule    | n8         |          3|
|    3 | capsule    | n8         |          4|
|    4 | instrument | n8         |          5|
+------+------------+------------+-----------+

Note the part_num

I really only need the part_num and value out of this (which i am getting), but i would like to group it in PHP by the part number.

For example something even as simple as printing this:

Part: (p1)
Values: 1, 2, 3, 4, 5, 6, 7.
Part: (n)
Values: 1, 2, 3, 4, 5.

PLEASE NOTE: I can't do this with mysql as I am using this data for other things and I don't want to be doing multiple database requests.

I hope i've made this clear enough, let me know if more info is needed.

Jacob · Accepted Answer · 2011-03-21 05:03:11Z

1

Assuming your current data is in the variable $data you can loop through the rows and create a new array $partnums.

$partnums = array();

foreach($data as $row) {
    if (!isset($partnums[$row['part_num']]))
        $partnums[$row['part_num']] = array();
    $partnums[$row['part_num']][] = $row['value'];
}

Now $partnums is an array that has the part_num's for keys... each of which references an array of values associated with that part_num.

To print out the values like you have suggested:

foreach($partnums as $partnum => $values) {
    printf('Part: (%s)'.PHP_EOL, $partnum);
    printf('Values: %s.'.PHP_EOL, implode(', ', $values));
}

edited Mar 21, 2011 at 5:03

answered Mar 21, 2011 at 4:54

Jacob

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3 Comments

dangermark Over a year ago

Hi Jacob, thanks for that. I kind of follow what you're saying but my array isn't quite right yet, it's looking like Array( [p1] => 7 [n8] => 5 ) Sorry to seem naive, i'm not sure how now to iterate through each separate value

dangermark Over a year ago

Ah!! Did you just edit this? I didn't see that last section :)

Jacob Over a year ago

I believe you may have looked at RDL's previous solution before he edited it.

RDL · Accepted Answer · 2011-03-21 04:53:27Z

0

You would use a loop go through the data. Something like this:

$results = [your query and fetch]

$array = array();
foreach ($results as $rs)
  $array[$rs['part_num']][] = $rs['value'];

answered Mar 21, 2011 at 4:53

RDL

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