Python dataframe class __init__ weird behaviour-CodePudding

So I'm trying to restructure files in my project and created a following class

File: merge.py

class DataFrame:
def __init__(self):
    self.df = pd.DataFrame()

in other file I'm calling it

File:merge_files.py

from merge import Dataframe
dfx = DataFrame()

here's the output for:

print(dfx)

OUTPUT:

<merge.DataFrame object at 0x81503d790>

and if I print following:

print(dfx.df)

OUTPUT:

Empty DataFrame
Columns: []
Index: []

I searched for hours and found no answer. Can someone explain this and propose how to get to empty dataframe using just dfx instead of dfx.df

Many thanks

CodePudding user response：

What your code currently does is create a generic object that has the field df that stores a pandas DataFrame. So the empty datafrrame is a field of the object, but not the object itself.

Instead, you want to inherit the pandas DataFrame class so that when you instantiate your DataFrame class, it's also a pandas DataFrame.

import pandas as pd
class MyDataFrame(pd.DataFrame):
    def __init__(self):
        super().__init__()
        
print(MyDataFrame())

CodePudding user response：

I end up modifying Michael's code so one method performs two tasks, see code below

class NewDataFrame(pd.DataFrame):
def __init__(self,df: pd.DataFrame):
    super().__init__(df)

Example of call:

1. df = NewDataFrame(None)
2. df = NewDataFrame(pd.DataFrame(columns=constant.COLUMNS_REPORT))
3. df = NewDataFrame(df_something)

Thank you all for your help