Deleting same values from an array

Hello, I have an array called $stems that has a bunch of numbers in it like 2, 5, 4, 4, 2, 6, 8. What I want to do is delete a section of the array that has the same number. In the example of the numbers I listed, I'd want to delete one of the number 4's, and one of the number 2's so that it would read this: 2, 5, 4, 6, 8 instead. I'm really clueless as to how to do this, any ideas? Thanks, Stephen Craton