如何解决：“列表索引必须是整数或切片，而不是 str”

Question

im new to python, still learning it and im trying to make a script that sends out emails to multiple emails but im having a problem with it. it keeps on printing out an error in line 9:

"list indices must be integers or slices, not str"

and im confused on what that means and what i need to do to fix that.

import smtplib
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart

email_list = ["First@email.com", "second@email.com", "third@email.com", "etc..."]

num = 0
for i in email_list:
    msg['To'] = email_list[i] #this line gives the error
    num = num + 1
    server.sendmail(email, email_list[i], text)

print("Emails Sent: " + num)

I expect the output to be, Emails Sent: 3, but it doesn't lol

Answer 1

In python for e in collections must be read as 'for each element e of the collection', meaning that e takes the value of each element in the collection.

In your example, i will take the values "First@email.com" then "second@email.com" etc.. and not 0, 1... as you seem to believe. However when you're doing email_list[i] you're trying to get the i'th value of your list. Which cannot works since we saw that i is a string.