CODEWITHSUNDEEP
pythonpandas
Ajay Chinni
Ajay Chinni

Reputation: 840

How to add new empty column sequentially

I have this Data frame with these columns

dd = pd.DataFrame({'a':[1],'1':[1],'2':[1],'4':[1],'6':[1],'b':[1]})

   a  1  2  4  6  b
0  1  1  1  1  1  1

I want to add the missing column numbers like col 3 and col 5 is missing in its sequential manner, I can surely do this which gives the expected output.

dd['3'] = 0
dd['5'] = 0
dd=dd.reindex(columns= ['a', '1','2','3','4','5','6','b'])

   a  1  2  3  4  5  6  b
0  1  1  1  0  1  0  1  1

I have thousands of columns I can't do it manually is there a way we can add them via a loop or something

Upvotes: 2

Views: 97

Answers (2)

Shubham Sharma
Shubham Sharma

Reputation: 71689

Let's filter the numeric columns then using get_loc obtain the location in the dataframe correspoding to the start and end location of the numeric columns, finally use reindex with fill_value=0 to reindex accordingly:

c = dd.filter(regex=r'^\d+$').columns
l1, l2 = dd.columns.get_loc(c[0]), dd.columns.get_loc(c[-1])
idx = np.hstack([dd.columns[:l1], np.r_[c.astype(int).min():c.astype(int).max() + 1].astype(str), dd.columns[l2 + 1:]])
dd = dd.reindex(idx, axis=1, fill_value=0)

   a  1  2  3  4  5  6  b
0  1  1  1  0  1  0  1  1

Upvotes: 3

sharathnatraj
sharathnatraj

Reputation: 1614

Please try this:

for i in range(1, int(df.columns[-2])):
    if str(i) not in df.columns:
        df.insert(i, str(i), 0)

Prints:

   a  1  2  3  4  5  6  b
0  1  1  1  0  1  0  1  1

Assuming this as per the comments that the numbered column sequence starts from second column till the second last column. The code also works if you have only one numbered column between start and end columns.

Upvotes: 1

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