Put all indexs of array in a comma separated string

Question

I have an array that looks like this:

array('first' => 'value1', 'second' => 'value2', ...);

How can I get all the keys and put them in a comma separated string?

At the very end I need something like this, to do a query:

values IN ('first','second',...)

Thanks

@Jack not quite. That will give them an array of the keys. They will then have to `implode()` that. — Patrick James McDougle, Jan 17 '13 at 13:44
Have a look at [this question](http://stackoverflow.com/questions/920353/php-pdo-can-i-bind-an-array-to-an-in-condition). It deals with a similar problem. — Till Helge, Jan 17 '13 at 13:45
@PatrickJamesMcDougle op already has `implode` tag on the question, so my comment should give enough information. — Ja͢ck, Jan 17 '13 at 13:47
BTW, instead of injecting that string directly, you really should make sure that you are using PDO prepared statements for this. http://php.net/manual/en/pdo.prepared-statements.php — Patrick James McDougle, Jan 17 '13 at 14:04

score 17 · Accepted Answer · answered Jan 17 '13 at 13:44

17

should be enough:

echo "'".implode("','", array_keys($array))."'";

answered Jan 17 '13 at 13:44

Rufinus

Comment deleted because I was being dumb. – Patrick James McDougle Jan 17 '13 at 13:45
nope, explode = string to array; implode = array to string – Rufinus Jan 17 '13 at 13:46
@PatrickJamesMcDougle hapens to the best of us :D – Rufinus Jan 17 '13 at 13:57

score 2 · Answer 2 · answered Jan 17 '13 at 13:45

2

array_keys will grab all the keys, implode will combine them into a string.

implode("','", array_keys($array));

answered Jan 17 '13 at 13:45

newtron

Ja͢ck · Answer 3 · 2013-01-17T14:01:38.817

2

The simple answer is to use array_keys() to get the array indices.

However, since you're using this in SQL, it's important to also properly escape the values:

$db = new PDO( ... );
$sql .= "value IN (" . 
        join(', ', array_map(array($db, 'quote'), array_keys($arr))) . ")";

Or, when you prefer using prepared statements:

$stmt = $db->prepare('... WHERE value IN (' . 
    join(',', array_fill(0, count($arr), '?')) . ')');
$stmt->execute(array_keys($arr));

edited Jan 17 '13 at 14:01

answered Jan 17 '13 at 13:51

Ja͢ck

IMHO it would be much better to use `VALUE IN (?)` and `->execute(array(implode("','",array_keys($array))` – Rufinus Jan 17 '13 at 13:56
1

@Rufinus I wouldn't say *much* better, but that's a good alternative :) – Ja͢ck Jan 17 '13 at 13:58

score 0 · Answer 4 · answered Jan 17 '13 at 13:46

0

$result = '';
$keys = array_keys($array);

foreach($keys as $key) { 
$result .= $key.',';
}

$result = rtrim($result, ',');

answered Jan 17 '13 at 13:46

Rami

this will lead to `first, second` not to `'first','second'` – Rufinus Jan 17 '13 at 13:47

score -1 · Answer 5 · answered Jan 17 '13 at 13:44

-1

Have a at array_keys. It seems like the thing you need. To combine the keys, use implode as suggested by many other users:

implode("','", array_keys($array));

answered Jan 17 '13 at 13:44

Ivaylo Strandjev

5 Answers5