How would you group/cluster these three areas in arrays in python?

Question

So you have an array

1
2
3
60
70
80
100
220
230
250

For a better understanding:

Answer 1

I assume you want a pretty-good-but-simple algorithim here.

If you know you want N clusters, then you can take the differences (deltas) between consecutive members of the (sorted) input list. E.g. in numpy:

 deltas = diff( sorted(input) )

Then you can place your cuttoffs where you find the N-2 biggest differences.

Things are trickier if you don't know what N is. Here you might place the cuttoffs whenever you see a delta greater than a certain size. This will then be a hand-tuned parameter, which is not great, but might be good enough for you.