How to delete all rows in a dataframe?

Question

I want to delete all the rows in a dataframe.

The reason I want to do this is so that I can reconstruct the dataframe with an iterative loop. I want to start with a completely empty dataframe.

Alternatively, I could create an empty df from just the column / type information if that is possible

Answer 1

Here's another method if you have an existing DataFrame that you'd like to empty without recreating the column information:

df_empty = df[0:0] 

df_empty is a DataFrame with zero rows but with the same column structure as df

Answer 2

The latter is possible and strongly recommended - "inserting" rows row-by-row is highly inefficient. A sketch could be

>>> import numpy as np >>> import pandas as pd >>> index = np.arange(0, 10) >>> df = pd.DataFrame(index=index, columns=['foo', 'bar']) >>> df Out[268]:     foo  bar 0  NaN  NaN 1  NaN  NaN 2  NaN  NaN 3  NaN  NaN 4  NaN  NaN 5  NaN  NaN 6  NaN  NaN 7  NaN  NaN 8  NaN  NaN 9  NaN  NaN