Distinguish the use of Python | [-1], [: -1], [:: -1], [2:: -1]

• Format
  list[start :end : Direction ]
  start——> Start subscript position
  end——> End subscript position
  Direction ——> Read direction . Default forward direction ,-1 Indicates reverse reading

import numpy as np
a=[1,2,3.4,5]
print(a)
[ 1 2 3 4 5 ]
print(a[-1]) # Forward reading the last element 
[5]
print(a[:-1]) # Forward read all except the last one 
[ 1 2 3 4 ]
print(a[::-1]) # Read all elements in reverse 
[ 5 4 3 2 1 ]
print(a[2::-1]) # Reverse from the third element （ Reverse subscript 2） Start reading , Until all 
[ 3 2 1 ]

original text