How to compare one array with the other one in Perl?

I have an array  called "diffNumbers". This array has some numbers in it. I also have another array which is called "lineNumbers".

What I want to do is to identify which numbers in the lineNumbers array are also in the diffNumbers array. If they are also in the diffNumbers array then I will push them to newLineNumbers array. Otherwise, I will push them to existingLineNumbers array.

I have a code that I started to write to do this, but I cannot figure out a way to identify if the numbers in the lineNumbers array are also in the diffNumbers array in the following if statement:

		foreach my $lineNumber (@$lineNumbers) {
			if $lineNumber is in the array of @diffNumbers{
				push(@newLineNumbers, $lineNumber);
			}else{
				push(@existingLineNumbers, $lineNumber);
			}
		}

Thanks,