Find element in a list of dicts based on value

Question

I am trying to find an element in a list, how can I do that? This is what I wrote:

user_list = [
    {'name': 'Alizom_12',
     'gender': 'f',
     'age': 34,
     'active_day': 170},
    {'name': 'Xzt4f',
     'gender': None,
     'age': None,
     'active_day': 1152},
    {'name': 'TomZ',
     'gender': 'm',
     'age': 24,
     'active_day': 15},
    {'name': 'Zxd975',
     'gender': None,
     'age': 44,
     'active_day': 752},
] 

def find_user(user_name):
    for items in user_list:
        if user_name == 'name':
            print(user_name+" exists")
        else:
            print(user_name+" does not exists")

when I print the following I want it to find the user:

find_user('Alizom_12')

Is it not a bit of a red flag that the loop variable isn't _used_ anywhere?! You should read a basic tutorial: https://sopython.com/wiki/What_tutorial_should_I_read%3F — jonrsharpe, Aug 03 '22 at 22:04
Wouldn't it also make more sense to write `for user in user_list:` as opposed to `items`? — martineau, Aug 03 '22 at 23:22

score 0 · Answer 1 · answered Aug 03 '22 at 22:05

0

You're close. You need to get the value in the dictionary

if user_name == items['name']:

answered Aug 03 '22 at 22:05

OneCricketeer

179,855
19
132
245

Thank you all. If I want to print the user information rather than just printing user exists, how can I do that? – John Aug 03 '22 at 22:11
Did you try `print(items)`? – OneCricketeer Aug 03 '22 at 22:30

Daniel Hao · Answer 2 · 2022-08-03T22:23:38.343

There are more than one places that your code has to be fixed:

Let's try to use the code snippet to point out them one by one.

First you can find the user_name by go through each dict. and the key name, secondly, it's better to return and not print.
Lastly, the last print should be out side of the for-loop, otherwise, you will get many repeated not found messages...


def find_user(user_name):
    for items in user_list:
        if items['name'] == user_name:
            return f'{user_name} exists. '
            #return items         # will return this user's dict. (all info)   *You have to comment prev. statement first. and uncomment this
        
    return f'{user_name} -  does not exists'


print(find_user('Alizom_12'))     #  Alizom_12 exists.
print(find_user('John Doe'))      #  John Doe -  does not exists

@John - if you have any further questions, please ask. Have ```updates``` - if user is found, it can return the ```whole dict. info```. — Daniel Hao, Aug 03 '22 at 22:13

score 0 · Answer 3 · answered Aug 03 '22 at 22:08

0

user_list = [
    {'name': 'Alizom_12',
     'gender': 'f',
     'age': 34,
     'active_day': 170},
    {'name': 'Xzt4f',
     'gender': None,
     'age': None,
     'active_day': 1152},
    {'name': 'TomZ',
     'gender': 'm',
     'age': 24,
     'active_day': 15},
    {'name': 'Zxd975',
     'gender': None,
     'age': 44,
     'active_day': 752},
] 

def find_user(user_name):
    userExists = False
    for items in user_list:
        for key, value in items.items():
            if key == 'name' and value == user_name:
                userExists = True
        
    if userExists is True:
        print(user_name+" exists")
    else:
        print(user_name+" does not exists")

find_user('Alizom_12')

answered Aug 03 '22 at 22:08

ScriptedChicken

153
1
6

Why loop over all keys? Also, don't use `is` for boolean comparison. Checking `is True` is redundant – OneCricketeer Aug 03 '22 at 22:31
1. My bad 2. https://stackoverflow.com/a/3257957/14250980 3. It makes for cleaner code when trying to explain these concepts to new beginners. – ScriptedChicken Aug 03 '22 at 23:12
`is True` is not the same as `is None`. Equality checking, not instance checking should be done for boolean types – OneCricketeer Aug 04 '22 at 14:18
https://stackoverflow.com/questions/27276610/boolean-identity-true-vs-is-true – OneCricketeer Aug 04 '22 at 14:26

Find element in a list of dicts based on value

3 Answers3