pandas - Extend Index of a DataFrame setting all columns for new rows to NaN?

Question

I have time-indexed data:

df2 = pd.DataFrame({ \'day\': pd.Series([date(2012, 1, 1), date(2012, 1, 3)]), \'b\' : pd.Series([0.22, 0.3]) })
df2 = df2.set_index(\'         


        

Answer 1

Use this (current as of pandas 1.1.3):

ix = pd.date_range(start=date(2012, 1, 1), end=date(2012, 1, 31), freq='D')
df2.reindex(ix)

Which gives:

               b
2012-01-01  0.22
2012-01-02   NaN
2012-01-03  0.30
2012-01-04   NaN
2012-01-05   NaN
[...]
2012-01-29   NaN
2012-01-30   NaN
2012-01-31   NaN

For older versions of pandas replace pd.date_range with pd.DatetimeIndex.