How to add an empty column in a dataframe using pandas (without specifying column names)?

Question

I have a dataframe with only one column (headerless). I want to add another empty column to it having the same number of rows.

To make it clearer, currently, the size of my data frame is 1050 (since only one column), I want the new size to be 1050*2 with the second column being completely empty.

jezrael · Accepted Answer · 2020-09-15 09:59:36Z

1

In pandas in DataFrame are always columns, so for new default column filled by missing values use length of columns:

s = pd.Series([2,3,4])

df = s.to_frame()

df[len(df.columns)] = np.nan
#what is same for one column df like
#df[1] = np.nan
print (df)
   0   1
0  2 NaN
1  3 NaN
2  4 NaN

edited Sep 15, 2020 at 9:59

answered Sep 15, 2020 at 9:49

jezrael

868k103 gold badges1.4k silver badges1.3k bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

aim_bee.1 Over a year ago

df[1] = np.nan doesn't change the size of the data frame and when I use df[len(df.columns)] = np.nan it gives the following error: AttributeError: 'Series' object has no attribute 'columns'

jezrael Over a year ago

@aim_bee.1 - Answer was edited, use df = s.to_frame() before my solution, because Series:

Collectives™ on Stack Overflow

How to add an empty column in a dataframe using pandas (without specifying column names)?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related