CODEWITHSUNDEEP
pythonpython-3.x
MennoSteenwijk
MennoSteenwijk

Reputation: 39

LinkedList in Python

I am looking for a solution for the following problem. I have an Excel file that I read with Pandas. Column A contains an identifier and column B also contains Identiers, but the identifiers in column B are linked to the identifier in Column A. example:

+----------+----------+ | Column A | Column B | +----------+----------+ | ID1 | ID5 | +----------+----------+ | ID1 | ID6 | +----------+----------+ | ID1 | ID7 | +----------+----------+ | ID2 | ID8 | +----------+----------+ | ID2 | ID9 | +----------+----------+ | ID3 | ID8 | +----------+----------+ | ID3 | ID9 | +----------+----------+ | ID3 | ID10 | +----------+----------+ | ID3 | ID11 | +----------+----------+

So now I want to have ID1 linked to ID5, ID6 and ID7. ID2 linked to ID8, ID9 etc

In Java I would use the linked list. What should I use in Python?

Thanks!

Upvotes: 1

Views: 608

Answers (3)

Merlin
Merlin

Reputation: 25629

Try this: 

dict(df.groupby('Column A')['Column B'].apply(list))

Upvotes: 0

user2285236
user2285236

Reputation:

Since you are using pandas to read, you can construct the dictionary with pandas methods:

df.groupby('Column A')['Column B'].agg(lambda x: list(x)).to_dict()
Out[42]: 
{'ID1': ['ID5', 'ID6', 'ID7'],
 'ID2': ['ID8', 'ID9'],
 'ID3': ['ID8', 'ID9', 'ID10', 'ID11']}

Upvotes: 2

Ryan Tam
Ryan Tam

Reputation: 43

Maybe a defaultdict with set?

from collections import defaultdict
ident_pair_dict = defaultdict(set)

for ind, row in df.iterrows(): # df is the pandas dataframe you read
    ident_pair_dict[row['Column A']].add(row['Column B'])

Upvotes: 2

Related Questions