CODEWITHSUNDEEP
python-3.xlistloopsdictionarytext
ChiBay
ChiBay

Reputation: 189

keeping certain values from list and dict

I have a dict d 

d = {'A1': ['Mike', 'Mouse'],
 'A2': ['Don', 'Duck'],
 'A3': ['Bart','Simp']}

and a list l

l = ['Sar', 'Mike', 'Duck', 'Hox12', 'Bart', '10r']

My goal is to create a new list new_l that does not have the items in l e.g. Mike that are also in d e.g. 'A1': ['Mike', 'Mouse'].

I would like my new_l to be 

new_l = ['Sar', 'Hox12', '10r]

I have tried

new_l = []
for k, v in d.items():
    if v not in l:
        new_l.append(v)

and

new_l = []
for names in l:
    if names not in v in d.items():
        new_l.append(names)

But they both do not give me my desired output.

How do I change my code to get my desired new_l?

Upvotes: 0

Views: 30

Answers (3)

LiamMcCoy
LiamMcCoy

Reputation: 11

You can also try this one-liner:

new_l = reduce(list.__add__, [list(set(items) - set(l)) for items in d.values()])

Upvotes: 1

rajender kumar
rajender kumar

Reputation: 412

use extend functionality to prepare a list using dict values.

new_l = []
d = {'A1': ['Mike', 'Mouse'],
 'A2': ['Don', 'Duck'],
 'A3': ['Bart','Simp']}
l = ['Sar', 'Mike', 'Duck', 'Hox12', 'Bart', '10r']
to_cmp_l = []
for k,v in d.items():
    to_cmp_l.extend(v)
for item in l:
    if item not in to_cmp_l:
        new_l.append(item)
print(new_l)

Upvotes: 1

R. Arctor
R. Arctor

Reputation: 728

s = set()
for v in d.values():
    s |= set(v)
new_l = [e in l if e not in s]

convert each value to set and build a set of all values in the dictionary. Build the new list by checking for membership in the set.

You could use a list instead of a set, though a set has certain advantages, namely that elements are unique and the membership test is a constant time operation.

|= is shorthand for adding elements to an existing set. Docs

Upvotes: 1

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