Question

我正在学习python，并且遇到了全局变量/列表的问题。我正在编写河内计划的基本手册，这是目前的程序：

pilar1 = [5,4,3,2,1,0]
pilar2 = [0,0,0,0,0,0]
pilar3 = [0,0,0,0,0,0]

def tower_of_hanoi():

    global pillar1
    global pillar2
    global pillar3

    print_info()

def print_info():

    global pillar1
    global pillar2
    global pillar3

    for i in range(4,-1,-1):
        print(pillar1[i], " ", pillar2[i], " ", pillar3[i])

我尝试了一些变体，但每次我收到错误＆＃34; NameError：全局名称＆＃39; pillar1＆＃39;未定义＆＃34;。

在此设置中处理全局列表的最佳方法是什么？如果可能的话，我更愿意只使用一个源文件。谢谢！

Answer 1

这是因为您已将其“声明”为pilar1，而不是pillar1

Answer 2

您遇到的问题是pilar与pillar不同。解决之后，您将不再需要global声明：

pilar1 = [5,4,3,2,1,0]
pilar2 = [0,0,0,0,0,0]
pilar3 = [0,0,0,0,0,0]

def tower_of_hanoi():    
    print_info()

def print_info():    
    for i in range(4,-1,-1):
        print(pillar1[i], " ", pillar2[i], " ", pillar3[i])

只有在非全局范围内分配全局变量时才需要使用全局变量，例如函数定义：

# global variable, can be used anywhere within the file since it's
# declared in the global scope
my_int = 5

def init_list():
    # global variable, can be used anywhere within the file after
    # init_list gets called, since it's declared with "global" keyword
    global my_list
    my_list = [1, 2, 3]

def my_function():
    # local variable, can be used only within my_function's scope
    my_str = "hello"

    # init's global "my_list" variable here, which can then be used anywhere
    init_list()
    my_list.append(5)

my_function()
print(my_list)

但是你不应该使用全局变量，而是使用函数参数来传递值。

Python全局列表

2 个答案: