I’ve got a dataframe and I want to keep a “base” (original copy) which I can work from later. However when I use it and try to create a new dataframe, it’s updating the original base copy too.

I’ve created a simple example which replicates my problem:

import pandas as pd

# create base df
base=pd.DataFrame([[1,2],[3,4]])

# simple function that does something to the df
def dosomething(df) :
    df[0]=[5,6]
    return(df)

# create a new df
new=dosomething(base)

# print new and base dfs
print(new)
print(base)

This gives the following output:

   0  1
0  5  2
1  6  4
   0  1
0  5  2
1  6  4

So both my “new” dataframe has updated as I’d expect, but also the “base” dataframe has (which I was expecting to stay as the original).

What am I missing?