python检查字典是否在列表中

Question

I have a list called clients_list full of dictionaries such as this:

    clients_list =
    [
            {'John Guy': [28, '03171992', 'Student']},
            {'Bobby Jones': [22, '02181982', 'Student']},
            {'Claire Eubanks': [18, '06291998', 'Student']},
    ]

How would I check to see if someone was in this list using the input answer? I have tried the code

elif answer in clients_list:
    print(f'{answer} is in our database.')

But it does not seem to work properly.

Answer 1

Try this

clients_list = [{'John Guy': [28, '03171992', 'Student']},
            {'Bobby Jones': [22, '02181982', 'Student']},
            {'Claire Eubanks': [18, '06291998', 'Student']}]

c= 'John Guy'

for item in clients_list:
    if c in item:
        print c + 'is in our database.'
        break

Answer 2

Suppose answer contains "John Guy" . Then this test if answer in clients_list asks if the string "John Guy" is in the list of dictionaries, which of course it isn't, because clients_list is a list of dictionaries, not strings. Now do you see why your test doesn't do what you expect?

This demonstrates juanpa.arrivilaga's point that the data structure doesn't really match what you are doing with it. If you want to do lookups on names, those names should be dictionary keys. Something like

clients_list = {
        'John Guy': [28, '03171992', 'Student'],
        'Bobby Jones': [22, '02181982', 'Student'],
        'Claire Eubanks': [18, '06291998', 'Student'],
        }

You might also consider making the dictionary values named tuples instead of lists.

Answer 3

If you want to match on keys, you can use set().union :

clients_list = [{'John Guy': [28, '03171992', 'Student']},
                {'Bobby Jones': [22, '02181982', 'Student']},
                {'Claire Eubanks': [18, '06291998', 'Student']}]

x = input('Enter a name:')

if x in set().union(*clients_list):
    print('Name found')
else:
    print('Name not found')

Answer 4

Commas between the list elements.

clients_list =[{'John Guy': [28, '03171992', 'Student']},
            {'Bobby Jones': [22, '02181982', 'Student']},
            {'Claire Eubanks': [18, '06291998', 'Student']}]

As for the issue, this should work

for d in clients_list:
    for person in d.items():
        if "John Guy" in person[0]:
            print (person[1])
            print (person[0]+" is in our database")

Answer 5

You can try doing it using the zip function:

clients_list = [{'John Guy': [28, '03171992', 'Student']}, {'Bobby Jones': [22, '02181982', 'Student']}, {'Claire Eubanks': [18, '06291998', 'Student']}]

name = "John Guy"
if name in list(zip(*clients_list))[0]:
     print(name + " is in database.")

Output:

John Guy is in database.

The list(zip(*clients_list)) will return a list containing a tuple with the names as such:

[('John Guy', 'Bobby Jones', 'Claire Eubanks')]

Then all you do is to take that one tuple of the list using [0] and check in that tuple if your the name you gave as input exists.

Or alternatively, you can unpack the single tuple of names:

names, = list(zip(*clients_list))

and the use it to check if your name is in there:

if name in names:
     print(name + " is in database.")

Answer 6

clients_list = [
            {'John Guy': [28, '03171992', 'Student']},
            {'Bobby Jones': [22, '02181982', 'Student']},
            {'Claire Eubanks': [18, '06291998', 'Student']}]

def get_name(answer):
    data = ("No Data Present in DB.",{'Error':'Not Found'})
    for index, val in enumerate(clients_list):
        if answer in val.keys():
            data =  (f'{answer} present in database & found at {index}', clients_list[index])
    return data

asnwer = input("Enter a Name")

found, value = get_name(asnwer)

print(found, value)
>>>Bobby Jones present in database & found at 1 {'Bobby Jones': [22, '02181982', 'Student']}