How is slicing useful in python code example

Example 1: slicing in python

word = "Example"

# Obtain the first 3 characters of "Example"
# E x a m p l e
# 0 1 2 3 4 5 6
# First 3 characters = "Exa"
sliced_word = word[:3] # Gives you "Exa"

# Everything after character #3 = "mple"
second_sliced_word = word[3:] # Gives you "mple"

Example 2: is : and :: the same in python slice

a[::-1]    # all items in the array, reversed
a[1::-1]   # the first two items, reversed
a[:-3:-1]  # the last two items, reversed
a[-3::-1]  # everything except the last two items, reversed