Posted by Markus Ernst on 07/06/06 08:52

Hi

While looping through an array I extract all keys on the fly, as in this
example:

$data = array(
array('name' => 'Helen', 'age' => '40'),
array('name' => 'Mark', 'email' => 'mark@xyz.com', 'age' => '90'),
);
$keys = array();
foreach ($data as $row) {
foreach ($row as $key => $value) {
// do other things here
$keys[$key] = 1;
}
}
$column_names = array_keys($keys);

Now my question is about the line
$keys[$key] = 1;

This overwrites existing entries and thus creates a set of unique keys.
This could also be done without overwriting:
if (!isset($keys[$key])) $keys[$key] = 1;

So I wonder which is more efficient - overwriting the array entry at
every loop, or checking for it with the if statement.

Thanks for a comment
Markus

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