value_counts rows pandas code example

Example 1: pandas count rows with value

len(df[df['score'] == 1.0])

Example 2: value_counts pandas

>>> index = pd.Index([3, 1, 2, 3, 4, np.nan])
>>> index.value_counts()
3.0    2
4.0    1
2.0    1
1.0    1
dtype: int64