Search array keys with wildcard

Question

Say I have the following array:

$arr = array(
   "number2"=>"valid",
   "number13"=>"valid"
);

and I need to find if there is a key that exists with number*.

For $arr, this would be true. For the following array:

$arr2 = array(
   "key"=>"foo",
   "key2"=>"foo2"
);

this would return false.

Answer 1

This one assumes number needs to be followed by an actual number (edit: or nothing at all), adjust the regular expression as necessary. For example, anything starting with 'number', you could use /^number/.

if(count(preg_grep('/^number[\d]*/', array_keys($arr))) > 0)
{
   return true;
}
else
{
   return false;
}