len(df[df['score'] == 1.0])
>>> df.count(axis='columns') 0 3 1 2 2 3 3 3 4 3 dtype: int64
In [37]: df = pd.DataFrame({'a':list('abssbab')}) df.groupby('a').count() Out[37]: a a a 2 b 3 s 2 [3 rows x 1 columns]