How to make a deepcopy of a dataframe with dataframes within it? (python)

Question

I want a copy of a dataframe which contains a dataframe. When I change something in the nested dataframe, it shouldn't change in the original dataframe.

I have a dataframe like this:

   0  1                                                  2
0  1  2  <__main__.PossibleCombinations object at 0x000...
1  4  5                                                  6

Generated with the next code:

import copy
import numpy as np
import pandas as pd


df = pd.DataFrame(data= [[1,2,3],[4,5,6]])

class PossibleCombinations:
    def __init__(self, dfCombinations, numberCombinations):
        self.dfCombinations = dfCombinations
        self.numberCombinations = numberCombinations

df.iloc[0,2] = PossibleCombinations(pd.DataFrame(data= [[1,2,3],[4,5,6]]),6)
print(df)

When I make a deepcopy of the hole dataframe and the nested dataframe and change something in the nested dataframe in the copy, the value also changes in the original.

deepCopy = copy.deepcopy(df)
deepCopy.iloc[0,2].dfCombinations = copy.deepcopy(df.iloc[0,2].dfCombinations)

deepCopy.iloc[0,2].dfCombinations.iloc[0,2] = "doei"

print(deepCopy.iloc[0,2].dfCombinations)
print(" ")
print(df.iloc[0,2].dfCombinations)

output:

   0  1     2
0  1  2  doei
1  4  5     6

   0  1     2
0  1  2  doei
1  4  5     6

but I want:

   0  1     2
0  1  2  doei
1  4  5     6

   0  1     2
0  1  2     3
1  4  5     6

What is the fix for this problem?

score 0 · Accepted Answer · answered Oct 18 '19 at 11:31

This is the fix:

import pickle
deepCopy = pickle.loads(pickle.dumps(df))

deepCopy.iloc[0,2].dfCombinations.iloc[0,2] = "doei"

print(deepCopy.iloc[0,2].dfCombinations)
print(" ")
print(df.iloc[0,2].dfCombinations)

output:

3
   0  1     2
0  1  2  doei
1  4  5     6

   0  1  2
0  1  2  3
1  4  5  6

This solves the problem!

How to make a deepcopy of a dataframe with dataframes within it? (python)

1 Answers1