Question

How do i go about seeing if my integer is in an array of integers…

eg i want to know if 7 is in an array of [ 1 3 4 5 6 7 8]

any ideas?

Thanks

Answer 1

There are several ways to do this depending on factors such as size of the array – how often you need to search, how often you need to add to the array etc. In general this is a computer science problem.

More specifically I’d guess there are three options likely to best fit your needs.

1. “Brute force”: just loop through the array looking for the value. Calling containsObject: on the NSArray will do this for you. Simple and probably fastest for small array sizes.
2. Copy the array into a set and use containsObject: to check for existence
3. Keep the values in the array, but sort the array and implement your own binary search – which is probably not as complex as it sounds.