Python dictionary comprehension with Pandas

Question

I am trying to create a dictionary from two columns of a DataFrame (df)

mydict={x :y for x in df['Names'] for y in df['Births']}

But all of the values are the same(the last value in the column)!

{'Bob': 973, 'Jessica': 973, 'John': 973, 'Mary': 973, 'Mel': 973}

I checked the column and it has many other values, what am I doing wrong?

Asked By: AboJoe

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Source

Answer 1

I think Abdou hit the nail on the head with dict(zip(dff['Names'], dff['Births'])), but if you want to do it with a dict comprehension you can do this:

    In [1]: import pandas as pd

    In [2]: df = pd.DataFrame(
       ...: [{'Births': 971, 'Names': 'Bob'},
       ...:  {'Births': 972, 'Names': 'Jessica'},
       ...:  {'Births': 973, 'Names': 'John'},
       ...:  {'Births': 974, 'Names': 'Mary'},
       ...:  {'Births': 975, 'Names': 'Mel'}])

    In [3]: {d['Names']: d['Births'] for d in df.to_dict(orient='records')}
    Out[3]: {'Bob': 971, 'Jessica': 972, 'John': 973, 'Mary': 974, 'Mel': 975}

Answered By: Lloyd Kirk

Answer 2

try
my_dict = {row.Names:row.Births for (index,row) in df.iterows()}

Answered By: Abi Vernekar

Python dictionary comprehension with Pandas

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