如何在python中的局部变量中存储全局变量名？

Question

所以我试图创建一个函数，让我简单地调用函数，并给它10个值和一个变量，它将随机地将该变量更改为提供的值之一。

import random

place = "NA"

def randomize (value1, value2, value3, value4, value5, value6, value7, value8, value9, value10, variable):
global variable
variable  = random.choice([value1, value2, value3, value4, value5, value6, value7, value8, value9, value10])

randomize ("Dungeon", "Plains", "Castle", "Prison", "Tavern", "Armory", "Docks", "Warehouse", "ThroneRoom", "Bedroom", place)

print place

然而，这告诉我以下内容：

SyntaxError: name 'variable' is local and global

Answer 1

在Python中，通常不会修改输入参数。我知道这是C中的标准，但是更容易返回值并将变量赋值给函数的输出：

import random

def randomize(*values):
    return random.choice(values)

place = "NA"
print place

place = randomize("Dungeon", "Plains", "Castle", "Prison", "Tavern", "Armory", "Docks", "Warehouse", "ThroneRoom", "Bedroom")
print place

Answer 2

实现您要实现的目标的一种方法是不将全局变量place作为参数传递给函数。

import random

place = "NA"

def randomize (value1, value2, value3, value4, value5, value6, value7, value8, value9, value10):      
   global place       
   place  = random.choice([value1, value2, value3, value4, value5, value6, value7, value8, value9, value10])

randomize ("Dungeon", "Plains", "Castle", "Prison", "Tavern", "Armory", "Docks", "Warehouse", "ThroneRoom", "Bedroom")

print place

编辑

正如您所指出的那样，您也希望将此函数用于其他变量，为此，您只需返回random.choice....并调用randomize函数即可根据需要更改任意数量的变量值。

下面的代码片段用于更改两个变量的值，一个是全局变量place，另一个是myVar

import random

place = "NA"

def randomize (value1, value2, value3, value4, value5, value6, value7, value8, value9, value10):
    return random.choice([value1, value2, value3, value4, value5, value6, value7, value8, value9, value10])

place = randomize ("Dungeon", "Plains", "Castle", "Prison", "Tavern", "Armory", "Docks", "Warehouse", "ThroneRoom", "Bedroom")

myVar = randomize ("Dungeon", "Plains", "Castle", "Prison", "Tavern", "Armory", "Docks", "Warehouse", "ThroneRoom", "Bedroom")

print place   
print myVar

Answer 3

对于1, 2, 3, ... n值，你应该使用list。您还需要编写更少的代码，因此它可以更好地扩展。你应该尽量避免使用global variables ...你可以找到in the global internet的原因。对于此示例，您甚至可以保存方法定义。

import random
places = ["Dungeon", "Plains", "Castle", "Prison", "Tavern", "Armory", "Docks",
          "Warehouse", "ThroneRoom", "Bedroom"]  # list with n elements...
place = random.choice(places)
print place