Python list index out of range error

Question

import pandas as pd
df = pd.read_csv("email_addresses_of_ALL_purchasers.csv")
all_emails = df["Email"]
real_emails = [] 
test_domains = ['yahoo.com', 'gmail.com', 'facebook.com', 'hotmail.com']
for email in all_emails: 
 email_separated = email.split("@")
 if email_separated[1] not in test_domains:
 real_emails.append(email) 
print real_emails

I'm trying to filter out different email account types. Why does this above code produce an error:

IndexError: list index out of range

• Max Noel: "List index out of range" is a pretty self-explanatory error message IMO. Take a look at the actual data that's causing the error.

Answer 1

Apparently one of your emails does not contain a @.

Put a print(email) as first statement of the loop, then you can see which email doesn't fit.

• SethMMorton: +1 Before anything else, when debugging you should print the variables so that what you expect to be in them is actually in them.

Answer 2

Try this:

import pandas as pd
df = pd.read_csv("email_addresses_of_ALL_purchasers.csv")
all_emails = df["Email"]
real_emails = [] 
test_domains = ['yahoo.com', 'gmail.com', 'facebook.com', 'hotmail.com']
for email in all_emails: 
 email_separated = email.split("@")
 try:
 if email_separated[1] not in test_domains:
 real_emails.append(email)
 except IndexError:
 print('Mail {} does not contain a @ sign'.format(email))
print real_emails

• DSM: We could use pandas directly too: print all_emails[~all_emails.str.contains("@")]

Answer 3

More robust to use partition here. If the @ is missing - domain will simply be the empty string

for email in all_emails: 
 name, delim, domain = email.partition("@")
 if domain and domain not in test_domains:

Also wikipedia has a list of unusual but valid email address examples that may surprise you