Python check if value exists in dictionary

Question

I've got a Python dictionary, as follows:

users = {'user': {'pw': 'password'}}

How do I check if the value exist in the dictionary?

I would receive a false in the following if statement:

if 'password' in users:
        return 'true'
else:
        return 'false'

You should organize your data in such a way that the operations you want to perform are cheap, and finding out whether a dictionary contains a value is already expensive, let alone a nested value. Also, there is pretty much never a reason to check whether a password is in use. It just leaks information and makes it easy to break into your system. — user2357112, Dec 06 '15 at 04:08
@user2357112 My intuition is that the OP won't understand what you have just said. — nbro, Dec 06 '15 at 04:09
@nbro: Mine too, but exposure to the information may be useful for future understanding, even if he doesn't understand it now. — user2357112, Dec 06 '15 at 04:13

Szymon · Answer 1 · 2015-12-06T04:09:22.363

You have a dictionary within a dictionary, so to check if any user (top level) has password (key 'pw') set to 'password', you can use:

return 'password' in (user['pw'] for user in users.itervalues())

Also note that the boolean values in Python are True and False. If you wanted to return strings 'true' and 'false', you can do:

return 'true' if 'password' in (user['pw'] for user in users.itervalues()) else 'false'

score -1 · Answer 2 · answered Dec 06 '15 at 04:05

-1

You would do

if users['user']['pw'] == 'password':
    return 'true'
else:
    return 'false'

answered Dec 06 '15 at 04:05

dursk

2 Answers2