Python simple email validity check

Question

In Python, if i wanted to write something that returns a boolean True as long as the @ symbol appears after the . symbol, how would I write this?

I have tried writing something like:

if myString[x] == "@" > myString[x] == ".":
     return True

but, I assume that this won't work because they're both essentially the same index. Looking for some explanation as well, just learning a lot of basics still. Thanks!

you want to know if the @ appears after or before `.` for email validation? — depperm, Sep 30 '16 at 19:56
`this.is.a.valid@email.address` and you algorithm fails this. — kennytm, Sep 30 '16 at 19:58
For email address checking, see http://stackoverflow.com/questions/8022530/python-check-for-valid-email-address. — kennytm, Sep 30 '16 at 20:00
I appreciate the info, I'm actually just trying to write this poor function for an assignment and having trouble. I understand that this wouldn't work well if I tried to implement this in the real world. Thanks for the info, though! — , Sep 30 '16 at 20:17
If it is homework, you should do it yourself. If you don't know the basics, like how to find the position of `@` and `.` in a string, google *"find position of character in string python"* — zvone, Sep 30 '16 at 21:56

score 1 · Answer 1 · answered Sep 30 '16 at 19:56

1

if str.index('@') > str.index('.'):
   return True;

answered Sep 30 '16 at 19:56

FallAndLearn

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This will result in an error if the string does not contain `@` or `.` – Efferalgan Sep 30 '16 at 20:00
Addtionally, it would be better to simply do `return str.index('@') > str.index('.')` – juanpa.arrivillaga Sep 30 '16 at 20:03
@Efferalgan : He was just asking about the syntax if you have read the question correctly. Moreover, the email validity itself is wrong as @>. is not a correct way to verify email. – FallAndLearn Sep 30 '16 at 20:05

score 1 · Answer 2 · answered Sep 30 '16 at 19:57

1

You could use a simple regular expression:

import re

rx = re.compile(r'\S+@\S+')

string = """This text contains an email@address.com somewhere"""

if rx.search(string):
    print("Somewhere in there is an email address")

See a demo on ideone.com.

answered Sep 30 '16 at 19:57

Jan

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This does not satisfy the constraints of the question (although it may of course satisfy the constraints of reality) – Nick Bastin Sep 30 '16 at 20:00
@NickBastin: Good Points - both :) – Jan Sep 30 '16 at 20:03

score 1 · Answer 3 · answered Sep 30 '16 at 20:07

1

return str.find('@') > str.find('.') and str.find('.') > -1

This will check that @ is after ., and that both symbols are present in the string. This is however a very bad way to check for email validity.

answered Sep 30 '16 at 20:07

Efferalgan

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Python simple email validity check

3 Answers3