CODEWITHSUNDEEP
python
Basilis Sokiss
Basilis Sokiss

Reputation: 11

Python lists find value by key

The function I call from the main program is

elif retrieve_user(user_login):
        print("Hello " + user_login + ", welcome!\n")

I use the function util.csv_to_dict('user.csv') and I want to find the name of users they inclound in user.csv file:

news_items = util.csv_to_dict('users.csv')
print("The list of contacts ie: \n", news_items)
for n in news_items:
    if n==username:
        print('O user found!!!!')
        return True
    else:
        return False

Its not work and I don't know the reason. Pls help.

Upvotes: 1

Views: 78

Answers (2)

Deyuan
Deyuan

Reputation: 56

I notice that you are utilizing dictionary in your code. Normally when dealing with dictionaries, I use exception handling to "increase efficiency" of my code. "Better to ask forgiveness than permission"

Alternative solution:

def check_user(username):
    news_items = util.csv_to_dict('users.csv')
    print("The list of contacts ie: \n", news_items)
    try:
        if news_items[username]:
            print('O user found!!!!')
            return True
    except:
        return False

Upvotes: 1

bousof
bousof

Reputation: 1251

I think your code should look more like:

news_items = util.csv_to_dict('users.csv')
print("The list of contacts ie: \n", news_items)
for n in news_items:
    if n==username:
        print('O user found!!!!')
        return True
return False

That way, it's only after looping on all keys, if the user wasn't found you return False value. In your original code, only the first iteration of the for loop is completed and you will return value True only if it matches the first one.

Don't hesitate if you need more explanations.

Upvotes: 1

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