Using conditions with CSV rows

Question

I'm looking at creating a very basic username and password program using an external CSV file. The program allows the user to input a username and password, afterwards an if statement checks whether the username and password match that of a row in the CSV document. If so then the corresponding user information is displayed.

The issue I'm having is to with my else: statement. If the user details don't match that of a row (wrong username or password) a notification should display. By adding an else line though, it checks per line so I receive more than one "Details entered incorrectly." messages. Also if the credentials are correct, the user information is displayed alongside "Details entered incorrectly" for every other row.

import csv

Username = input("Username: ")
Password = input("Password: ")

with open('data.csv', 'rt', newline='') as file:

    open_file = csv.reader(file)

for row in open_file:
    if row[0] == Username and row[1] == Password:
        print("Secret phrase: ", row[2])
    else:
        print("Incorrect user details.")

Any ideas on how I could alter my code to fix this? Much appreciated!

Noctua · Accepted Answer · 2014-01-22 21:16:31Z

3

There's something lovely in python, called the for-else. This else clause, belonging to a for-loop instead of an if, is executed if the loops exits normally (the iterator runs out):

for row in open_file:
    if row[0] == Username and row[1] == Password:
        print("Secret phrase: ", row[2])
        break # stop searching and skip the for-else.
else:
    print("Incorrect user details.")

I don't quite understand what you mean with

Also if the credentials are correct, the user information is displayed alongside "Details entered incorrectly" for every other row. Could you elaborate or give an example?

answered Jan 22, 2014 at 21:16

Noctua

5,2381 gold badge20 silver badges23 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

user2100672 Over a year ago

This doesn't stop the "Incorrect user details." message appearing if the user details match that of the second row for example - the message appears with the user information below.

Noctua Over a year ago

@user3149629: I don't get what you mean, could you perhaps give an example csv and credentials for which it fails?

Collectives™ on Stack Overflow

Using conditions with CSV rows

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related