Slice notation in Python

Slice notation in Python

#create list
#index [0,1,2,3] #for ref below
a =    [5,6,17,20]

#a[start:stop]  # items start through stop-1
a[2:4]

[17, 20]

#a[start:]      # items start through the rest of the array
a[2:]

[17, 20]

#a[:stop]       # items from the beginning through stop-1
a[:3]

[5, 6, 17]

#a[:]           # a copy of the whole array
a[:]

[5, 6, 17, 20]

Slice in Python with negative number

a[-1]    # last item in the array

20

a[-2:]   # last two items in the array

[17, 20]

a[:-2]   # everything except the last two items

[5, 6]

You can also adjust the step, defaults to 1

#a[start:stop:step] #here will jump by index of 2 rather than default of one
a[0:4:2]

[5, 17]