Add one row to pandas DataFrame

Question

I know that pandas is designed to load fully populated DataFrame but what should I do if I need to create an empty DataFrame and then add rows, one by one. Can anyone help me with the best possible way?

I successfully created an empty DataFrame with :

res = DataFrame(columns=('lib', 'qty1', 'qty2'))
Then I can add a new row and fill a field with :

res = res.set_value(len(res), 'qty1', 10.0)
 

How can I add a new row to my DataFrame with different columns type ?

Answer 1

You can try the following :

>>> import pandas as pd
>>> import numpy as np
>>> df = pd.DataFrame(columns=['lib', 'qty1', 'qty2'])
>>> for i in range(5):
>>>     df.loc[i] = [np.random.randint(-1,1) for n in range(3)]
>>>
>>> print(df)
    lib  qty1  qty2
0    0     0    -1
1   -1    -1     1
2    1    -1     1
3    0     0     0
4    1    -1    -1

[5 rows x 3 columns]

Hope this works!