题解 | #牛客网用户练习的平均次日留存率#

import pandas as pd
import datetime as dt

df = pd.read_csv("nowcoder.csv", sep=",")
pd.set_option("display.width", 300)  # 设置字符显示宽度
pd.set_option("display.max_rows", None)  # 设置显示最大行
pd.set_option("display.max_columns", None)

df.date=pd.to_datetime(df.date).dt.date
df1=df.copy()

df1['date']=df1.date + dt.timedelta(days=1)
total = pd.merge(df,df1,how='inner',on=['user_id','date'])

print(round(total.user_id.count()/df.user_id.count(),2))