I’m trying to write to a text file using Python. The text file contains an existing line of text which is: "admin, adm1n" (admin being username, and adm1n being password). I added a new username and password (makay, makay1) on a new line, but when I try to re-call admin using the adm1n password, it turns out that the new line is being appended to "adm1n". Any suggestions would be helpful for creating an invisible newline.
Code snippet:
existing_users = open('user.txt', 'r+')
new_username = input("Please create a new username: ")
new_password = input("Please create a new password: ")
existing_users.write(f"\n{new_username}, {new_password}")
print(f"You have successfully registered the user {new_username}! Please remember to exit program.")
existing_users.close()
which outputs the text file as:
admin, adm1n
makay, makay1
HOWEVER, when I print out the list of passwords, I see that it changes "adm1n" to "adm1n\n".
Please help!
>Solution :
It looks like your issue is related to how you’re appending a new user and password to your file and how you’re reading from it afterward, rather than how you’re writing the data. When you write the new username and password with "\n{new_username}, {new_password}", you’re correctly adding a newline before the new user’s data, which should not affect the last character of the previous line.
However, if when you read from the file and notice that "adm1n" has become "adm1n\n", it suggests that the newline character is being included as part of the password when you’re reading it back, not when you’re writing it. This often happens because reading lines from a file includes the newline character at the end of each line, except possibly the last line if it doesn’t end with a newline character.
To ensure that newline characters are not included when you read the data back, you should strip them from the lines. Here’s how you can read usernames and passwords from the file without including newline characters in the passwords:
# Open the file to read existing users
with open('user.txt', 'r') as file:
users = [line.strip().split(", ") for line in file.readlines()]
# Print the usernames and passwords to verify
for username, password in users:
print(f"Username: {username}, Password: {password}")
In this snippet, line.strip().split(", ") is used to both remove leading and trailing whitespace (including newline characters) from each line with strip() and then split the line into a username and a password using split(", "). This way, you will get the correct values without trailing newlines in your passwords.
Regarding your writing issue, your existing approach seems correct for appending a new line for each new user and password. If you’re still facing issues, make sure that your file reading logic correctly handles the format and consider opening the file in append mode (‘a’ or ‘a+’ if you also need to read) when only adding new entries to avoid potential issues with file cursors in ‘r+’ mode. However, for the use case you’ve provided, your writing code should work as intended, assuming the file cursor is at the end of the file when you start writing. If you find the cursor is not at the end for some reason, you can explicitly move it there with existing_users.seek(0, 2) before writing.