In PythonLanguage:
>>> ar = range(100, 110)
>>> ar
[100, 101, 102, 103, 104, 105, 106, 107, 108, 109]
>>> ar[4] # the fifth element
>>> ar[:5] # first five elements
[100, 101, 102, 103, 104]
>>> ar[5:] # from element #5 onwards
[105, 106, 107, 108, 109]
>>> ar[-3:] # from the third-last onwards
[107, 108, 109]
>>> ar[4:6] # from element #4 (incl) to element #6 (excl)
[104, 105]
>>> ar[:-4] # from beginning to the #4 last element (excl).
[100, 101, 102, 103, 104, 105]
>>> ar[1:8:2] # every second element from #1 (incl) to #8 (excl)
[101, 103, 105, 107]