Python csv.DictReader 返回 KeyError

Question

I'm trying to create a script that reads/writes to a csv file depending on user input. Pretty much it simulates a password manager. However, when i tried to view it through the script using csv.DictReader, it returns KeyError.

The csv file was created as a blank and the data were inputted through the script itself.

import csv

with open('Pass.csv') as csv_file:

    csv_reader = csv.DictReader(csv_file, delimiter=',')
    for lines in csv_reader:
        print(f'{row["application"]} | {row["ID"]} | {row["password"]}')

I've noticed that if i change the

print(f'{row["application"]} | {row["ID"]} | {row["password"]}')

to

print(lines)

it returns the following output:

OrderedDict([(None, ['application', 'ID', 'password'])])
OrderedDict([(None, ['asd', 'dsa', 'asd'])])

So my question is why does it return None in the first place which seems to be the issue that caused the KeyError to arise.

In the link is the csv file i've used to test the DictReader: http://www.filedropper.com/pass_1

Answer 1

I ran your exact code and could not reproduce your error. After inputting two entries, I get:

>>> readPass()
Application | ID | Password
ap1 | id1 | pw1
application | ID | password
ap2 | id2 | pw2

As you can see, the printing is working fine, but you do have a bug in that you are writing new headers with every entry to the CSV file.