题解 | #多报名表的运动项目人数统计#

import pandas as pd

df1 = pd.read_csv("items.csv")
df2 = pd.read_csv("signup.csv")
df3 = pd.read_csv("signup1.csv")
#合并
df4 = pd.concat([df2, df3], join="outer")
df5 = pd.merge(df4,df1,how='inner',on='item_id')
print(df5.groupby("item_name")["employee_id"].count())