Question

I have a specific key in array that I would like to get, however it is suffix by an incremental counter.

Array
(
  [nombre] => Carlos
  [apellido] => Delfino
  [sum1] => Array
            (
              [0] => Apple
              [1] => Banana
              [2] => Liquor
            )
  [sum3] => Array
            (
              [0] => Grapes
            )
)

I am planning to put the sum keys (sum1 & sum3) on a new array. A foreach is on my mind however I am doubting should I use regex or PHP string function for this.

foreach($arr as $k => $v)
{
  //I'm lost here on how to match keys with at least `sum` word on it
}

Answer 1

This will check if it word begins with sum. If there are going to be other keys that being with sum and have non-integer values after them, a regexp would be needed.

foreach($arr as $k => $v)
{
  if (strpos($k, 'sum') === 0) {
     // key begins with 'sum'
  }
}

Regexp way:

foreach($arr as $k => $v)
{
  if (preg_match('/^sum[0-9]+$/', $k)) {
     // key begins with 'sum' and is followed by an integer
  }
}