如何解决python的全局变量问题

Question

我目前正在制作一个刽子手游戏，我有一个全局变量来指示要绘制刽子手的哪一部分。问题是我需要在函数中更改此变量 (drawRate) 的值，因为稍后我将在不同的函数中需要它，但 python 不会让我这样做。有什么办法可以解决这个问题吗？

import tkinter as tk
import turtle
import string
from functools import partial
from draw_hangman import drawHangman

word = 'hello'
shown_text = list('-'*len(word))
draw = drawHangman()
drawRate = 0

def whenPressed(button, text):
    button.config(state = 'disabled')
    ind = []
    local_word = list(word)
    for i in local_word :
        if i == text:
            trash = local_word.index(i)
            ind.append(trash)
            local_word.pop(trash)
            local_word.insert(trash, '-')
    if len(ind) != 0:
        for i in ind:
            shown_text.pop(i)
            shown_text.insert(i, text)
        lab.config(text = ''.join(shown_text))
        for i in shown_text:
            if i == '-':
                trash = True
        if trash != True:
            print('You Won!')
    else:
        trash = draw[drawRate]
        exec(trash)
        drawRate+=1
        

root = tk.Tk()
t = turtle.Turtle()
alphabet = list(string.ascii_lowercase)
lab = tk.Label(root, text = '-'*len(word), font = (None, 15), width = 30)
lab.grid(row = 0, columnspan = 13)
for i in alphabet:
    btn = tk.Button(root, text=i)
    command = partial(whenPressed, btn, i)
    btn.config(command=command)
    row = (alphabet.index(i) // 13)+1
    column = alphabet.index(i) % 13
    btn.grid(row=row, column=column, sticky="news")

变量draw 是一个列表，其中包含绘制刽子手图形的命令：

draw = [
    '''t.penup()
t.fd(200)
t.rt(90)
t.fd(200)''',
    '''t.down()
t.lt(270)
t.fd(400)''',
    '''t.rt(90)
t.fd(400)''',
    '''t.rt(90)
t.fd(300)''',
    '''t.rt(90)
t.fd(75)
t.dot(75)''',
    't.fd(100)',
    '''t.lt(90)
t.fd(60)''',
    '''t.back(120)
t.fd(60)
t.rt(90)''',
    '''t.fd(75)
t.lt(30)
t.fd(100)''',
    '''t.back(100)
t.rt(60)
t.fd(100)''']

Answer 1

您必须在 whenPressed() 函数中将此变量声明为 global，如下所示：

def whenPressed(button, text):
    global drawRate
    ...

Answer 2

我是新手，如果这不正确，请提前原谅我，但你能不能在函数开始时声明/引入你的全局变量：global drawRate

def whenPressed(button, text):
    global drawRate 
    button.config(state = 'disabled')
    ind = []
    local_word = list(word)
    for i in local_word :
        if i == text:
            trash = local_word.index(i)
            ind.append(trash)
            local_word.pop(trash)
            local_word.insert(trash, '-')
    if len(ind) != 0:
        for i in ind:
            shown_text.pop(i)
            shown_text.insert(i, text)
        lab.config(text = ''.join(shown_text))
        for i in shown_text:
            if i == '-':
                trash = True
        if trash != True:
            print('You Won!')
    else:
        trash = draw[drawRate]
        exec(trash)
        drawRate+=1

Answer 3

尝试在 whenPressed 函数的顶部将 drawRate 定义为 global

喜欢

import turtle
import string
from functools import partial
from draw_hangman import drawHangman

word = 'hello'
shown_text = list('-'*len(word))
draw = drawHangman()
drawRate = 0

def whenPressed(button, text):
    global drawRate
    button.config(state = 'disabled')
    ind = []
    local_word = list(word)
    for i in local_word :
        if i == text:
            trash = local_word.index(i)
            ind.append(trash)
            local_word.pop(trash)
            local_word.insert(trash, '-')
    if len(ind) != 0:
        for i in ind:
            shown_text.pop(i)
            shown_text.insert(i, text)
        lab.config(text = ''.join(shown_text))
        for i in shown_text:
            if i == '-':
                trash = True
        if trash != True:
            print('You Won!')
    else:
        trash = draw[drawRate]
        exec(trash)
        drawRate+=1
        

root = tk.Tk()
t = turtle.Turtle()
alphabet = list(string.ascii_lowercase)
lab = tk.Label(root, text = '-'*len(word), font = (None, 15), width = 30)
lab.grid(row = 0, columnspan = 13)
for i in alphabet:
    btn = tk.Button(root, text=i)
    command = partial(whenPressed, btn, i)
    btn.config(command=command)
    row = (alphabet.index(i) // 13)+1
    column = alphabet.index(i) % 13
    btn.grid(row=row, column=column, sticky="news"```