A collection of 19 tips on PHP functions on arrays. Clear answers are provided with tutorial exercises on searching keys and values, sorting arrays, merging two arrays, looping on array elements, expanding and truncating arrays. Special topics are: How Do You If a Key Is Defined in an Array? How To Sort an Array by Values? How To Join a List of Keys with a List of Values into an Array? How To Merge Values of Two Arrays into a Single Array? How To Use an Array as a Queue? How To Pad an Array with the Same Value Multiple Times?