Thank you for sharing this Dev2, nicely written article.

you can add this: Slicing with positive and negative index

Code:

s = "Welcome to scaler"
s1 = s[3 : -7]
print("positive start index, negative end index:", s1)
# above slice operation can also be written as
s2 = s[-14 : 10]
print("negative start index, positive end index:", s2)

Output:

positive start index, negative end index: come to
negative start index, positive end index: come to

Check this String Slicing in Python article on Scaler Topics.