Slice Array

a = [
    10, 20, 30, 40, 50, 60, 70, 80, 90
]
a
[10, 20, 30, 40, 50, 60, 70, 80, 90]

type(a)
list

a[4:8]
[50, 60, 70, 80]

a[:4]
[10, 20, 30, 40]

a[4:]
[50, 60, 70, 80, 90]

a[:]
[10, 20, 30, 40, 50, 60, 70, 80, 90]

a[-1]
90

a[-2]
80

# get last 2 items
a[-2:]
[80, 90]

# every except last 2 iteme
a[:-2]
[10, 20, 30, 40, 50, 60, 70]

# all items reverse
a[::-1]
[90, 80, 70, 60, 50, 40, 30, 20, 10]

a[1::-1]
[20, 10]

a[1::-2]
[20]

# get the first three items reversed
a[2::-1]
[30, 20, 10]

# all items eversed and ignore the last item
a[-2::-1]
[80, 70, 60, 50, 40, 30, 20, 10]

# Remove last 2 items, reverse all the rest of the items
a[-3::-1]
[70, 60, 50, 40, 30, 20, 10]

# last two items reversed
a[:-3:-1]
[90, 80]

a[:-4:-1]
[90, 80, 70]

# Everything except the last 3 items, reversed
a[-4::-1]
[60, 50, 40, 30, 20, 10]