UnboundLocalError：分配前引用的本地变量'playercount'

Question

自我解释，当我运行此命令时，即使我之前已将变量playercount分配为全局变量，也会出现标题中显示的错误。我在这里搞砸了是什么？

import discord
import asyncio
import mysql.connector
from discord.ext.commands import Bot
from discord.utils import get


mydb = mysql.connector.connect(
  host='no',
  database='no',
  user='no',
  password='no'
)

cursor = mydb.cursor()


client = Bot('!')
@client.event
async def on_ready():
  print('===========')
  print('Bot running')
  print('===========')

global playercount
playercount = 0

@client.event
async def on_message(message):
  if message.content == '?help':
    helpMessage = discord.Embed(title="""Use ?joingame to join the game and follow instructions 
given.""")
    await message.channel.send(embed=helpMessage)

  if message.content == '?joingame':
   playercount = playercount + 1
   player = message.author.id
   add_player = "INSERT INTO user_info (userNum, UserId) VALUES (" + str(playercount) + ", " + 
str(player) + ")"
   cursor.execute(add_player)
   next_player = "SELECT userNum FROM user_info"
   cursor.execute(next_player)
   numberPlay = cursor.fetchall()[0][0]
   print(numberPlay)

Answer 1

playercount是全局变量。这意味着从函数中只能读取它，而不能对其进行修改。更改方法是在函数内使用global关键字。

关于为什么计数器总是重置为0的原因，这可能是因为在启动应用程序时，它会启动多个实例。因此，您需要将该值写入文件文本（txt或csv）或数据库中。

Answer 2

global playercount
playercount = 0

问题在于此行，因为变量在函数外部，因此不需要将其声明为全局变量删除该全局行并运行代码