def cal(s) :

    n = len (s)

    for i in range(n):

        if s[i] == " " :     #如果为空格字符

            p = i

        if s[i] == " :" :

            q = i

t =  + int(s[q+1:])

return t

图 b

import pandas as pd

import matplotlib.pyplot as plt

df = pd.read_excel("shared bikes.xlsx")

bike = [ "哈罗单车","摩拜单车",

"美团单车","青桔单车"]

sm = [0] * 4

avg = [0] * 4

days = 31

for i in  :

    t = cal(df.at[i, "结束时间"]) - cal(df.at[i, "开始时间"])

    for j in range(4):

        if df.at[i, "App 类型"] == bike[j] :

            break

for i in range(4):

    avg [i] = sm[i] / days

plt.figure(fig size = (12,4))

x = bike

y =

plt.bar (x,y)

plt.show()

n = df.groupby ("App 类型", as_index = True).用户编号.

图b

(提示：占总人口比重=年龄段人口数/总计人口数×100) )