while loop in a python class

Question

I am trying to incorporate a regex check for user input in my class. I want a scenario where users can't proceed to enter their name until they enter a valid email address. The current code i have isn't working as expected.

I suppose a while-loop is in order here but i am struggling to implement that in this class. Any assistance is much appreciated.

class test:  
 def __init__(self):     
    self.email = input("Enter your email: ")
    email_check = re.search(r'[\w.-]+@[\w.-]+.\w+', self.email)
    if email_check:
        print ('email valid')
    else:
        print ('email not valid')
        self.email = input("Enter your email: ")            
        sys.exit(0)
     self.name = input("Enter your name:  ")

score 1 · Answer 1 · answered Oct 11 '16 at 03:11

1

You can do it like this.

while True:
    self.email = input ("Enter email:")
    if valid_email:
        break

Substitute valid_email with your way of validating the email address.

You may also be interested in Python check for valid email address? for ways to validate an email address.

answered Oct 11 '16 at 03:11

v7d8dpo4

1,399
8
9

Thank you. This is exactly what i was looking for. – jebjeb Oct 11 '16 at 03:49

agg3l · Answer 2 · 2016-10-11T03:02:28.660

First of all - you should not implement any activity of this kind into __init__ method, as one is intended for object fields initialization first place. Consider dedicated 'check_email' method, or whatever name applies best.

Now, regarding your case:

class test:
    def __init(self):
       # whatever initialization applies
       pass

    def init_emails():
        emails = []
        proceed = True
        # if you really in need of do/while loop
        while proceed:
            email = self.input_email()
            # your logic for input
            if email is not None:
                emails.append(email)
            # invalid input or cancel
            else:
                 proceed = False
        return input

     def input_email(self):
         value = input('Enter your email:')
         # TODO: validate/check input
         return proper_value

I second the comments that this doesn't belong in `__init__` or probably even in a class at all. User interaction should probably happen outside the class unless it is specifically a class to implement user interaction. Your class should probably just `raise` an error if it finds itself populated with invalid data. — tripleee, Oct 11 '16 at 03:49

score 0 · Answer 3 · answered Oct 11 '16 at 03:11

   class test:  
     def __init__(self):     
         self.email = self.get_name()

     def get_name(self) :
         while True:
            x = input("Enter your email: ")
            if (re.search(r'[\w.-]+@[\w.-]+.\w+', x)) :
                return x

score 0 · Answer 4 · answered Oct 11 '16 at 04:33

This script functions as described, in the end printing the name and email. If you need to use python2.7, use raw_input instead of input. I used for i in range instead of while True to avoid an endless loop.

#!/usr/bin/env python3

import re
import sys


class Test(object):
    def __init__(self):
        self.email = None
        self.name = None

    def get_email(self):
        for i in range(3):
            email = input('Enter your email: ')
            if re.search('[\w.-]+@[\w.-]+.\w+', email):
                return email
        print('Too many failed attempts!')
        sys.exit(1)

    def get_name(self):
        for i in range(3):
            name = input('Enter your name: ')
            if name:
                return name
            print('Too many failed attempts!')
            sys.exit(1)

    def initialize(self):
        self.email = self.get_email()
        self.name = self.get_name()
        print('"{}" <{}>'.format(self.name, self.email))


if __name__ == '__main__':
    t = Test()
    t.initialize()

score 0 · Answer 5 · answered Oct 11 '16 at 05:06

0

Instead of input, try to use raw_input. Like this:

self.email = raw_input("Enter your email:")

There'll be no error anymore. Hope this helps.

answered Oct 11 '16 at 05:06

Harv

446
5
12

1

In Python 3, 'input` is the equivalent of Python 2's `raw_input` (see https://www.python.org/dev/peps/pep-3111/). Based on the usage of the print function (rather than statement) in the original code, I would assume the OP is using Python 3. – mgwilliams Oct 11 '16 at 05:15

while loop in a python class

5 Answers5