PHP array_replace without creating keys

Question

I am trying to overwrite the elements of one array with values from another – without creating additional elements in the process.

For example:

Answer 1

Try this:

$result = array_replace($base, array_intersect_key($replace, $base));

Answer 2

You can use array_intersect_key and array_merge to do it:

$result = array_merge($base, array_intersect_key($replace, $base));

array_intersect_key isolates those elements of $replace with keys that already exist in $base (ensuring that new elements will not appear in the result) and array_merge replaces the values in $base with these new values from $replace (while ensuring that keys appearing only in $base will retain their original values).

See it in action.

It is interesting to note that the same result can also be reached with the order of the calls reversed:

$result = array_intersect_key(array_merge($base, $replace), $base);

However this version does slightly more work, so I recommend the first one.

Answer 3

the following should do it:

foreach ($replace as $k => $v)
   if (isset($base[$k])) $base[$k]=$v;

Answer 4

I can't think of a built in method for that, however, it would be trivial with a loop and array_key_exists.

foreach( $replace as $k => $v )
{
   if ( array_key_exists( $k, $base ) )
      $base[ $k ] = $v;
}

Answer 5

print_r(array_intersect_key($replace, $base));