Phone validater using python

Question

You are given a number input, and need to check if it is a valid phone number.
A valid phone number has exactly 8 digits and starts with 1, 8 or 9.
Output "Valid" if the number is valid and "Invalid", if it is not.

Sample Input
81239870

Sample Output
Valid

Answer 1

what we need to do is:

basic version
▪︎take the input as string
▪︎check if length is 8. len() is a builtin function that can be also used for string type
▪︎check if all characters are digits. we can use the string method .isdigit()
▪︎check if first character is in "189"

advanced version
▪︎use regex

Answer 2

Dawit Yitagesu ,

if you need more help, please show us your code.

thanks!

Answer 3

Why not check the first character and then check the length of the string? Or check the length first, it's faster that way

Answer 4

Dawit Yitagesu

Use the len() function, just pass in the string and it'll return the length

Answer 5

Dawit Yitagesu

I'm not sure how it works in python, but the pattern should look somewhat like this:

^[189]\d{7}$

Make sure to import the re library

Answer 6

How can I check the length

Answer 7

I was wondering if u guys help me using regx