copy part of array

[saltwater]

i have an 2 dimensional array
$myArray=['somestring']['someotherstring']='morestringhere';
now I want to copy the second dimension where the first dimention equals 'somestring', this is what i try but it doesnt work, php gives an error that's its not an array

$subArray='somestring';
$secondArray=$myArray[$subArray];

now I'd want $secondArray['someotherstring'] the equal 'morestringhere' ..
ie, you copy the second dimension of the array, I know I could do this with a loop, but isn"t their some kind of function or way in PHP to do it faster?

Thanks in advance,
Bruno