how to create a dictionary using multiple lists with unique keys

Question

I'm trying to add key, value to an existing dictionary from a pre-defined list. Below is an example:

# I created players dictionary : 
players = {'gyms_visited': [],
 'player_id': [4],
 'player_name': 'cynthia',
 'player_pokemon': {},
 'time_played': 30.9}

I'm trying to add the list a, b to my players dictionary that I created above:

a = ['player_id', 'player_name','time_played', 'player_pokemon', 'gyms_visited']
b = [2, 'teri', 22.2, {}, []]

Also, is there a way to make Player_id's value (4, 2) as keys to the players dictionary ( This is what I'm trying to achieve):

{4: {'gyms_visited': [],
     'player_name': 'cynthia',
     'player_pokemon': {},
     'time_played': 30.9},
 2: {'player_name':'teri',
     'time_played':22.2,
     'gyms_visited': [],
     'player_pokemon':{}}

i have an existing dictionary called players , which has variables assigned {'gyms_visited': [], 'player_id': [4], 'player_name': 'cynthia', 'player_pokemon': {}, 'time_played': 30.9} — Pary kam, Jul 02 '17 at 14:15
your first player cynthia, is it already in a dictionary ? or did you at some point have her in a list ? — Rayhane Mama, Jul 02 '17 at 14:16
yes, cynthia is already in the dictionary ... i m trying to add another dictionary from list[a] and [b] — Pary kam, Jul 02 '17 at 14:18

Rayhane Mama · Answer 1 · 2017-07-02T14:56:59.360

All you need is:

# to change already existing dict
players = {players['player_id']:{key:value for key,value in players.items() if key != 'player_id'}}
# make dict from lists a and b
z = {b[a=='player_id']: {key:value for key,value in zip(a,b) if key !='player_id'}}
# group both
players={**players,**z}

Details Below:

First you will need to change your already made dict to the desired output type like this:

players = {players['player_id']:{key:value for key,value in players.items() if key != 'player_id'}}
print(players)

will output:

{4: {'gyms_visited': [], 
    'player_name': 'cynthia', 
    'player_pokemon': {}, 
    'time_played': 30.9}}

then you take your two lists a and b and make an additional dict out of them like this:

z = {b[a=='player_id']: {key:value for key,value in zip(a,b) if key !='player_id'}}
print(z)

will output:

{2: {'player_name':
    'teri', 'time_played': 22.2, 
    'player_pokemon': {}, 
    'gyms_visited': []}}

and Finally, you just put them in the same dict as follows:

players={**players,**z}
print(players)

output:

{4: {'gyms_visited': [],
    'player_name': 'cynthia',
    'player_pokemon': {},
    'time_played': 30.9},
 2: {'player_name': 'teri',
    'time_played': 22.2, 
    'player_pokemon': {},
    'gyms_visited': []}}

Please notice that you can do this in a loop if you want to add some more membres. For exemple consider these new lists:

a = ['player_id', 'player_name','time_played', 'player_pokemon', 'gyms_visited']
b = [6, 'new_Name', 66.6, {}, []]

by doing the same as before:

z = {b[a=='player_id']: {key:value for key,value in zip(a,b) if key !='player_id'}}
players={**players,**z}

you get as output:

{4: {'gyms_visited': [], 
    'player_name': 'cynthia', 
    'player_pokemon': {}, 
    'time_played': 30.9}, 
 2: {'player_name': 'teri', 
    'time_played': 22.2, 
    'player_pokemon': {}, 
    'gyms_visited': []}, 
 6: {'player_name': 'new_Name', 
     'time_played': 66.6, 
     'player_pokemon': {}, 
     'gyms_visited': []}}

You can refer to these links about merging dicts and **dicts for a better understanding.

Here is also a link for the built-in zip method.

no problem, don't forget to accept the answer if it suited your needs by clicking on the check mark for future users who might be interested in the answer as well — Rayhane Mama, Jul 02 '17 at 14:53

score 0 · Answer 2 · answered Jul 02 '17 at 15:26

from itertools import izip
from pprint import pprint

# Edit your existing dict
>>> players2 = {players.pop('player_id')[0]: players}
>>> pprint(players2)
{4: {'gyms_visited': [],
     'player_name': 'cynthia',
     'player_pokemon': {},
     'time_played': 30.9}}

# Add new player info
>>> players2.update({b[0]: {k: v for k, v in izip(a, b[1:])}})
>>> pprint(players2)
{2: {'gyms_visited': [],
     'player_name': 'teri',
     'player_pokemon': {},
     'time_played': 22.2},
 4: {'gyms_visited': [],
     'player_name': 'cynthia',
     'player_pokemon': {},
     'time_played': 30.9}}

Note: Whenever you're working with some iteration code, it's worth checking out the built-in itertools package. izip, for eaxample, improves over zip by returning an iterator instead of a list.

Happy to help; I use pokemon examples for unit tests ;) Please don't forget to select the answer with the checkmark at the left, thanks. — BoltzmannBrain, Jul 03 '17 at 02:36

how to create a dictionary using multiple lists with unique keys

2 Answers2