# arr[start (inclusive) : end (exclusive) : increment]
arr = [1, 2, 3, 4, 5]
a = arr[1 : 4]
b = arr[2 : ] # Second idx defaults to len(arr)-1
c = arr[ : 3] # First idx defaults to 0
d = arr[0 : 4 : 2]
print(a) # [2, 3, 4]
print(b) # [3, 4, 5]
print(c) # [1, 2, 3]
print(d) # [1, 3]