Searching a list in a text file using Python

Question

I have a program that registers an account and I am now working on a function to log said account in. I have saved the lists "usernames" and "passwords" to separate text files.

usernames = []
passwords = []
usernames.append(username)
passwords.append(password)

usernamesFile = open("usernames.txt","a")
for usernames in usernames:
    usernamesFile.write("%s\n" % usernames)
usernamesFile.close()

passwordsFile = open("passwords.txt", "a")
for passwords in passwords:
    passwordsFile.write("%s\n" % passwords)
passwordsFile.close()

while True:
    loginUsername = raw_input("Enter your username: ")
    usernamesFile = open("usernames.txt", "r")
    lines = usernamesFile.readlines() 
    if loginUsername in usernames:
        index = usernames.index(username)
        break
    else:
        print "Username not found"
        continue

My problem is, even though I have tested the text file and it has saved all of the usernames I have registered, the search still comes back "Username not found". I am not an expert in Python so if you could please explain in a simple way that would be great!

It doesn't look like your code ever does anything with lines, which I'm guessing is what you wanted to search through? (also: as a side note: even if you're just learning python, you should immediately purge the idea of ever storing a list of passwords in the clear). — David Makogon
– David Makogon, Commented Dec 28, 2017 at 12:25

Vijesh · Accepted Answer · 2017-12-28 12:34:19Z

1

You have not used lines read from usernames.txt file in your code for searching the username in it. So, modify your code as:

usernames = []
passwords = []
usernames.append(username)
passwords.append(password)

usernamesFile = open("usernames.txt","a")
for usernames in usernames:
    usernamesFile.write("%s\n" % usernames)
usernamesFile.close()

passwordsFile = open("passwords.txt", "a")
for passwords in passwords:
    passwordsFile.write("%s\n" % passwords)
passwordsFile.close()

while True:
    loginUsername = raw_input("Enter your username: ")
    usernamesFile = open("usernames.txt", "r")
    lines = usernamesFile.readlines() 
    if loginUsername in lines:
        index = lines.index(username)
        break
    else:
        print "Username not found"
        continue

answered Dec 28, 2017 at 12:34

Vijesh

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Comments

johnII · Accepted Answer · 2017-12-28 12:29:38Z

0

It is because you are writing this way

usernamesFile.write("%s\n" % usernames)

adding "\n" to the end of each username so your condition

if loginUsername in usernames:

is always False unless you remove the "\n" or you add it with loginUsername

answered Dec 28, 2017 at 12:29

johnII

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