可视化图形不正常只有一条柱状图

问题遇到的现象和发生背景

可视化图形不正常

问题相关代码，请勿粘贴截图

#coding=gbk
from selenium import webdriver
import time
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
import re
import pandas as pd
import lxml.html
import requests
from PIL import Image
from io import BytesIO


opt = Options()
opt.add_experimental_option('excludeSwitches', ['enable-automation'])
opt.add_argument('--disable-blink-features')
opt.add_argument('--disable-extensions')
opt.add_argument('--disable-blink-features=AutomationControlled')
driver = webdriver.Chrome(options=opt) # 创建driver对象
driver.get('https://www.acfun.cn/u/1075162') #打开页面
html=driver.page_source #访问整个页面的内容
time.sleep(2)
driver.close() #关闭页面


xp=lxml.html.fromstring(html) #lxml对象
units=xp.xpath('//figcaption') #没有text()
df = pd.DataFrame()


df = None
for u in units:
    w = {}
    w["标题"]=u.xpath('./p [@class="title line"]/text()')[0]
    w["观看与弹幕"]=u.xpath('./p [@class="play-info"]/text()')[0]
    w["日期"] = u.xpath('./p [@class="date"]/text()')[0]

    if w["标题"]==[]:
        print('无')
    df1 = pd.DataFrame([w])
    df = pd.concat([df,df1], ignore_index=True)


    a = re.findall(r'\d+[.]\d+', w["观看与弹幕"])[0]
    print(a)
    a=float(a)

print(df)
print(df.dtypes)


import pandas as pd

df=pd.DataFrame({'观看量':[a]},index=[w["标题"]])
import matplotlib.pyplot as plt
plt.rcParams['font.sans-serif'] = ['SimHei'] # 指定默认字体

pd.to_numeric(df['观看量']).plot(kind='bar')

plt.show()

运行结果及报错内容

plt.show()只有一条柱状图

我的解答思路和尝试过的方法

尝试改字符串，字符串改不成功

我想要达到的结果

因为你只保存了最后一组数据啊
帮你做了点修改，你试试：

#coding=gbk
from selenium import webdriver
import time
from selenium import webdriver
from selenium.webdriver.chrome.options import Options
import re
import pandas as pd
import lxml.html
import requests
from PIL import Image
from io import BytesIO
 
 
opt = Options()
opt.add_experimental_option('excludeSwitches', ['enable-automation'])
opt.add_argument('--disable-blink-features')
opt.add_argument('--disable-extensions')
opt.add_argument('--disable-blink-features=AutomationControlled')
driver = webdriver.Chrome(options=opt) # 创建driver对象
driver.get('https://www.acfun.cn/u/1075162') #打开页面
html=driver.page_source #访问整个页面的内容
time.sleep(2)
driver.close() #关闭页面
 
 
xp=lxml.html.fromstring(html) #lxml对象
units=xp.xpath('//figcaption') #没有text()
df = pd.DataFrame()
 
 
df = None
volume=[]
title=[]
for u in units:
    w = {}
    w["标题"]=u.xpath('./p [@class="title line"]/text()')[0]
    w["观看与弹幕"]=u.xpath('./p [@class="play-info"]/text()')[0]
    w["日期"] = u.xpath('./p [@class="date"]/text()')[0]
 
    if w["标题"]==[]:
        print('无')
    df1 = pd.DataFrame([w])
    df = pd.concat([df,df1], ignore_index=True)
 
 
    a = re.findall(r'\d+[.]\d+', w["观看与弹幕"])[0]
    print(a)
    volume.append(float(a))
    title.append(w['标题'])
 
print(df)
print(df.dtypes)
 
 
import pandas as pd
 
df=pd.DataFrame({'观看量':volume},index=title)
import matplotlib.pyplot as plt
plt.rcParams['font.sans-serif'] = ['SimHei'] # 指定默认字体
 
pd.to_numeric(df['观看量']).plot(kind='bar')
 
plt.show()