UnboundLocalError:在assignmen之前引用了局部变量“gold”

Question

在你决定因为我没有读其他问题而把我扔出窗外之前，我已经苦苦寻找了这么久。事实上，我发现了很多答案，但是它们在不同的上下文中，我不知道如何在代码中使用它们，因此我得出结论，与其浪费时间在其他问题上，而不是浪费时间来回答我的问题，而是问出我得到的确切错误，这对我更有利。在

import time
import random
inventory = []
gold = 0
rawfish = ["Mackarel", "Cod", "Salmon", "Herring", "Tuna"]
trash = ["Old Shoe", "Thin Bone", "Rusted Empty Box", "Plank Fragment"]
special = ["Copper Ring"]

print"  _           _       _       _        ______ _     _     _ "            
print" | |         | |     (_)     ( )      |  ____(_)   | |   (_)"            
print" | |     ___ | |_ __  _ _ __ |/ ___   | |__   _ ___| |__  _ _ __   __ _ "
print" | |    / _ \| | '_ \| | '_ \  / __|  |  __| | / __| '_ \| | '_ \ / _` |"
print" | |___| (_) | | |_) | | | | | \__ \  | |    | \__ \ | | | | | | | (_| |"
print" |______\___/|_| .__/|_|_| |_| |___/  |_|    |_|___/_| |_|_|_| |_|\__, |"
print"               | |                                                 __/ |"
print"               |_|                                                |___/ "
time.sleep(2)
print".       .                                     /|    /|     "
print" \     /                o                      |     |     "
print"  \   /   .-. .--..--.  .   .-. .--.       o   |     |     "
print"   \ /   (.-' |   `--.  |  (   )|  |           |     |     "
print"    '     `--''   `--'-' `- `-' '  `-      o   |  o  |     " 
time.sleep(2)
print "In this current version the first item in your inventory is sold."

def sell_function():
    if inventory[0] in rawfish:
        sold = inventory.pop(0)
        gold = gold+5
        print "You have sold a", sold, "for 5 gold coins!"
    elif inventory[0] in trash:
        sold = inventory.pop(0)
        gold = gold+5
        print "You have recycled a", sold, "for 1 gold coins!"
    elif inventory[0] in special:
        sold = inventory.pop(0)
        gold = gold+5
        print "You have sold a", sold, "for 10 gold coins!"
    else:
        print "Shopkeeper:'You can't sell that.'"

def fish_function():
    random_fishingchance = random.randrange(1,32)
    if 1 <= random_fishingchance < 3:
        inventory.append("Mackarel")
        print "You have reeled in a Mackarel!"
        time.sleep(0.5)
        print "You place it into your inventory"
    elif 3 <= random_fishingchance < 5:
        inventory.append("Cod")
        print "You have reeled in a Cod!"
        time.sleep(0.5)
        print "You place it into your inventory"
    elif 5 <= random_fishingchance < 7:
        inventory.append("Salmon")
        print "You have reeled in a Salmon!"
        time.sleep(0.5)
        print "You place it into your inventory"
    elif 7 <= random_fishingchance < 9:
        inventory.append("Herring")
        print "You have reeled in a Herring!"
        time.sleep(0.5)
        print "You place it into your inventory"
    elif 9 <= random_fishingchance < 11:
        inventory.append("Tuna")
        print "You have reeled in a Tuna!"
        time.sleep(0.5)
        print "You place it into your inventory"
    elif 11 <= random_fishingchance < 16:
        inventory.append("Old Shoe")
        print "You have reeled in an Old Shoe..."
        time.sleep(0.5)
        print "You place it into your inventory"
    elif 16 <= random_fishingchance < 21:
        inventory.append("Thin Bone")
        print "You have reeled in a Thin Bone..."
        time.sleep(0.5)
        print "You place it into your inventory"
    elif 21 <= random_fishingchance < 26:
        inventory.append("Rusted Empty Box")
        print "You have reeled in a Rusted Empty Box..."
        time.sleep(0.5)
        print "You place it into your inventory"
    elif 26 <= random_fishingchance < 31:
        inventory.append("Plank Fragment")
        print "You have reeled in a Plank Fragment..."
        time.sleep(0.5)
        print "You place it into your inventory"
    elif 31 <= random_fishingchance < 32:
        inventory.append("Copper Ring")
        print "You have reeled in a ring shaped object covered in mud."
        print "After cleaning it you notice it is a Copper Ring!"
        time.sleep(0.5)
        print "You place it into your inventory"
    else:
        print "It seems your fishing line has snapped!"


def action_function():
    while True:
        action = raw_input("Do you want to 'sell'  'fish'  'inventory' 'money' or 'quit'?")
        if action == "quit":
            break
            end
        if action == "sell":
            sell_function()
        if action == "fish":
            print "You throw your reel..."
            time.sleep(10)
            fish_function()
        if action == "inventory":
            print "You begin to open your inventory"
            time.sleep(0.5)
            print inventory
        if action == "money":
            print gold
        if action == "gold":
            print gold
action_function()

现在，我得到的错误是“sell_function()”。当我运行程序/游戏时，直到我输入“sell”并进入。我希望从库存中删除第一个项目，并根据项目的类型添加一定数量的“gold”。然而，当我这样做的时候，它会想到：

^{pr2}$

Answer 1

由于这一行，gold = gold+5python认为gold是一个局部变量，当您实际调用函数sell_function()时，不会从全局变量{}获取{}的值。在

这是因为函数中的局部变量是在解析函数定义时决定的。在

如果要修改全局变量，请使用global语句：

def sell_function():
    global gold
    if inventory[0] in rawfish:
       sold = inventory.pop(0)
       gold = gold+5

Answer 2

审查功能范围。因为要给gold赋值，所以python会创建一个新变量。然后尝试将其递增5，这样它将尝试获取新的“gold”的值，这会抛出错误。在

UnboundLocalError: local variable 'gold' referenced before assignment

在所有更改“gold”的函数中将其声明为全局变量。在

^{pr2}$