Move Value in PHP Array to the Beginning of the Array

Question

I have a PHP array similar to this:

0 => \"red\",
1 => \"green\",
2 => \"blue\",
3 => \"yellow\"

I want to move yellow to index

Answer 1

EDITED

This is an update based on the question and liking the generic aspects of the answer by Peter Bailey. However, the code is too function/memory intensive for me so below just does a simple swap of the $from and $to values. This method does not cause the array in question to be resized at all, it simply swaps to values within it.

Second Edit: I added in some more argument checking as mentioned in the comments.

function moveValueByIndex( array $array, $from=null, $to=null )
{
  // There is no array, or there are either none or a single entry
  if ( null === $array || count($array) < 2 )
  {
    // Nothing to do, just return what we had
    return $array;
  }

  if ( null === $from )
  {
    $from = count( $array ) - 1;
  }

  if ( null === $to )
  {
    $to = 0;
  }

  if ( $to == $from )
  {
    return $array;
  }

  if ( !array_key_exists($from, $array) )
  {
    throw new Exception( "Key $from does not exist in supplied array." );
  }

  $value = $array[$from];
  $array[$from] = $array[$to];
  $array[$to] = $value;

  return $array;
}

Forgive me if I should have just added this in a comment to Peter's post.. it just was too long to inline all of this there :/