I have two arrays like this:

```
$arr1 = Array ( [1] => ab [2] => cd [at] => ef )
$arr2 = Array ( [1] => gh [2] => ij [at] => kl )

```

I want to combine these two arrays to this array:

```
$arr3 = Array ( [1] => ab-gh [2] => cd-ij [at] => ef-kl )

```

The keys are the same in the two arrays so I imagine that it is possible to join the values of the arrays with a "-" between like above.

I have googled and tried almost anything (merge, combine, join) but I can't figure it out. Any suggestions?