What is error in "phone Number validation ". it failed 4th case.

Question

import re

def isValid(s):

# 1) Begins with 1 or 8 or 9

# 2) Then contains 8 digits

Pattern = re.compile(r"^(1/8/9)?[8]")

return Pattern.match(s)

# Code
s = input()

if (isValid(s)):

print ("Valid")

else :

print ("Invalid")

Answer 1

Maybe repeat the chapter to understand the syntax.
Use [] for sets of characters and {} for quantification (also ? + *)

Answer 2

Starts with 1, 8 or 9: ^[189]
Contains 8 digits (=7 more) : [0-9]{7}
Then it should end: $

Answer 3

There will be needed the end with 8 digits. You can first test your code on the Playground and see what happend. This can be done with printing of few variables.

https://code.sololearn.com/cx1tfbykB3pp/?ref=app