PHP: How to find difference of 2D arrays?

[shAnk]

I have two multidimensional arrays.. with same data... what happens is.. values in one array may be changing internally in one multidimensional array.. here is my array...\[code\]$previousA = array();$previousA["t"] = array("twitter","picasa");$previousA["d"] = array("youtube","gmail");$freshA = array();$freshA["t"] = array("twitter","picasa","gmail");$freshA["d"] = array("youtube");\[/code\]at any time total values will be four "twitter","picasa","youtube","gmail" which may inter change from $\[code\]previousA["t"]\[/code\] <=> \[code\]$previousA["d"]\[/code\] now i want to know which values change from \[code\]$previousA["t"]\[/code\] to $\[code\]previousA["d"]\[/code\] comparing with $freshA