pandas統計表類別個數df.value_counts()

統計數據表裏某列的類別個數：value_counts()

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
%matplotlib inline

df=pd.DataFrame('id'=[1,2,1,1,3,3,2,2])
df['id'].value_counts()

#或者比較複雜的寫法
df.groupyby(['id'],as_index=False)['id'].agg({'統計':'count'})  #count是統計函數