CODEWITHSUNDEEP
pythonpandas
Kong
Kong

Reputation: 2412

Pandas create dataframe from a dictionary of 2D arrays

How can I create a dataframe from a dictionary of 2D arrays such that each element in the dataframe is an array? For example, I would like df.iloc[0]["A"] below to return a [0,0,0]

import pandas as pd
import numpy as np

data = {"A":np.zeros([100,3]), "B":np.zeros([100,3]), "C":np.zeros([100,3])}
df = pd.DataFrame.from_dict(data)
# print(df.iloc[0]["A"]) = [0,0,0]

Upvotes: 1

Views: 1046

Answers (2)

Rick M
Rick M

Reputation: 1012

If you're willing to accept them being Python lists instead of np.arrays, you can do this:

data = {"A": np.zeros([100,3]).tolist()}
df = pd.DataFrame.from_dict(data)

print(df.iloc[0]["A"])
[0.0, 0.0, 0.0]

Upvotes: 1

Quang Hoang
Quang Hoang

Reputation: 150745

I would use MultiIndex:

df = pd.DataFrame({k:x.ravel() for k,x in data.items()},
                  index=pd.MultiIndex.from_product([np.arange(100), np.arange(3)]))

Then df.loc[0,'A'] gives you a series:

0    0.0
1    0.0
2    0.0
Name: A, dtype: float64

Upvotes: 2

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