Find key in one array according to another value from another array in PHP

Question

I've received this data from an app. My parameter list:

catids = 1, 2, 3
subscriptions = 1, 1, 0 [ 0 = keep subscribed and 1 = unsubscribe for catids in this order]
appuser_id = XXX

Now I have to update my subscription table according to data received. The schema is as follows:

--cat_id--appuser_id
  1     |     10    |
  2     |     10    |
  3     |     10    |   
  4     |     20    |
  5     |     20    |
---------------------

So how can I do this neatly considering query performance? The approach I could think of is:

Get all subscriptions whose value is 1.
Find out respective catids for values found in step 1.
Delete those entries from table.

I can reach up to step 1 only. I can't think of a way to match entries found in step 1 with their respective catid.

$cat = '1,2,3';
$subs = '1,1,0';

$catA = explode(',',$cat);
$subsA = explode(',',$subs);

$deleteSubList = array();
foreach($subsA as $v){
    if($v == 1){
        array_push($deleteSubList,$v);
    }
}

print_r($deleteSubList);

This gives me Array ( [0] => 1 [1] => 1 ). How do I know that it belongs to one of the categories from $catA array?

mpaepper · Accepted Answer · 2013-02-17 17:22:11Z

1

You need to remember your keys:

foreach($subsA as $key => $v){
        if($v == 1){
            $deleteSublist[$key] = $v;
        }
    }

Then $deleteSublist will be an array which has as keys all the ids of your array.

foreach($deleteSublist as $key => $value) {
   // Delete $cat[$key]
}

answered Feb 17, 2013 at 17:22

mpaepper

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6 Comments

Gimali Over a year ago

ahh.. that easy! thanks man. I got the 1 and 2 catid out of $catA array now. That's what I needed.

Gimali Over a year ago

another question, how to delete both of the records now? I don't think doing it in loop is best way since length of catA array can be anything. any help regarding that?

SeanWM Over a year ago

I don't believe this will work. You're just getting the key of subsA which he's not looking for. He wanted the category id (catA). Check my solution down below.

mpaepper Over a year ago

@Gimali One option is to use $deleteSublist[$key] = $cat[$key]; so you already have all the values you want to delete in your array. Then use that array for a mysql query

SeanWM Over a year ago

@Gimali I'd recommend you checking my answer. This solution will not work for you.

|

SeanWM · Accepted Answer · 2013-02-17 17:31:17Z

1

$cat = '1,3,3';
$subs = '1,1,0';

$catA = explode(',', $cat);
$subsA = explode(',', $subs);

for ($i = 0; $i <= count($subsA); $i++) {
    if ($subsA[$i] == 1) {
        $deleteSubList[$catA[$i]] = $subsA[$i];
    }
}
print_r($deleteSubList);

And to remove:

foreach($deleteSubList as $key => $value) {
    mysql_query("DELETE FROM tbl WHERE cat_id = " . $key);
}

answered Feb 17, 2013 at 17:31

SeanWM

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2 Comments

Gimali Over a year ago

I tried your code with following data $cat = '1,2,3,'; $subs = '1,1,0'; and I got Array ( [0] => 1 [1] => 1 [2] => 1 ) as output. Now how will I come to know which category to delete out of this?

Gimali Over a year ago

Sorry, I had to accept @Galen answer as it's nearly best and quickest way both in terms of finding catids and forming the query avoiding it to run in loops. Thank you very much for support.

Galen · Accepted Answer · 2013-02-17 21:04:15Z

0

Here's an easier way to do it

$deleteSubList = array_filter( array_combine( $catA, $subsA ) );

$sql = sprintf( "delete from table where cat_id in(%s) and appuser_id=%s", implode( ',' array_keys( $deleteSubList ) ), $appuser_id );

edited Feb 17, 2013 at 21:04

answered Feb 17, 2013 at 17:42

Galen

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2 Comments

Gimali Over a year ago

Wonderful! I tried your code, for $cat = '1,2,3'; $subs = '1,1,0'; and it gave me this sql, delete from table where cat_id in(12) and appuser_id=10 . Instead it should be like - delete from table where cat_id in(1,2) and appuser_id=10 right ? How to get this now ? I'm all set to accept this answer now.

Gimali Over a year ago

yea.. changed implode(array_keys( $deleteSubList ) ) to implode( ',', array_keys( $deleteSubList ) ) to get correct query.

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