Pass the name of the dataframe into each for row for a new column in a list of dataframes Python-CodePudding

I have a list of dataframes, I want to add a new column to each dataframe that is the name of the dataframe.

df_all = [df1,df2,df3]

for df in df_all:
    df["Loc"] = df[df].astype.(str)

Boolean array expected for the condition, not object

is this possible to achieve?

CodePudding user response：

You can't do this, python objects have no possibility to know their name(s).

You could emulate it with:

df_all = [df1, df2, df3]

for i, df in enumerate(df_all, start=1):
    df['Loc'] = f'df{i}'

Alternatively, use a dictionary:

df_all = {'df1': df1, 'df2': df2, 'df3': df3}

for k, df in df_all.items():
    df['Loc'] = k

CodePudding user response：

It can be done with using the system's locals() dictionary, which contains variable names and references, and the is operator to match.

df1, df2, df3 = pd.DataFrame([1, 1, 1]), pd.DataFrame([2, 2, 2]), pd.DataFrame([3, 3, 3])

df_all = [df1, df2, df3]

_df = k = v = None
for _df in df_all:
    for k, v in locals().items():
        if v is _df and k != '_df':
            _df["Loc"] = k

print(*df_all, sep='\n\n')

   0  Loc
0  1  df1
1  1  df1
2  1  df1

   0  Loc
0  2  df2
1  2  df2
2  2  df2

   0  Loc
0  3  df3
1  3  df3
2  3  df3