pandas - write a column of csv from pd.Series which is longer than row lines

Question

How to write or overwrite a column of csv from pd.Series, where the later is longer than original row lines? I use the following code:

df.loc[:, col_name] = pd.Seriese(new_value)

Where col_name is the column need to be modified, new_value is a list containing new values, this list is longer than table's row lines.

Then write csv with df.to_csv(file_name, index=False, header=True)

But it only writes original maximal rows of table.

Answer 1

How about using pd.concat ?

Before:

df1 = pd.DataFrame(data=[
    [2,3],
    [2,3],
    [1,5],
    [3,3]
], columns=['Test1', 'Test2'])

>>      Test1   Test2
   0    2       3
   1    2       3
   2    1       5
   3    3       3

Cast Series longer than number of rows into a DF:

df2 = pd.DataFrame(
    data=[9,8,2,1,5],
    columns=["Test1"]
)

Concat remaining column(s) with axis=1 to concatenate column-wise:

pd.concat([
    df2,
    df1[['Test2']]
], axis=1)

>>      Test1   Test2
   0    9       3.0
   1    8       3.0
   2    2       5.0
   3    1       3.0
   4    5       NaN