Python 2.7 使用%s以字符串形式打印时，将使用旧版本的全局变量

我是编程新手，这是我第一次尝试Python中的独立项目。我决定通过为一个班级项目创建一个简单的文本冒险来挑战自己，我遇到了一个小问题

在这个游戏中，玩家选择一个化身。我将这个化身存储为一个全局变量

Toon

，因为它在整个游戏中都被引用以确定正确的响应

在引言中，有一段将向玩家介绍第一个场景。我通过code academy学到了我称之为“%method”的方法，玩家选择的化身应该在这一段中提到，但它使用了

Toon

的初始值，该值初始化为：“我做错了什么

我确保全局

Toon

变量被正确更新，因为我让游戏打印出

Toon

的当前值，并且它是正确的

这里是我的代码的一个截断版本，相关的代码片段按照它们在我的代码中的顺序呈现

# global declaration of Toon, and preparing the introduction paragraph for text wrapping
    Toon = ""
    introduction = """ "Hello %s, this is the US Military. You have been selected in the most recent draft as a candidate to serve your country. Please report to your nearest deafting outpost for your pre-enlistment interview, ASAP." [...] "Hello %s, I am Commander Sheperd. Please have a seat." """ % (Toon, Toon)
    introduction_paragraph = textwrap.wrap(introduction, width = 70)

#player chooses their avatar

choice = raw_input("Who do you choose?")
process(choice)
global Toon
if choice == "1":
    print ""
    print "Greetings player 1!"
    print ""
    Toon = "player 1"
    sit1()
elif choice == "2":
    print ""
    print "Salutations, player 2!"
    print ""
    Toon = "player 2"
    sit1()
elif choice == "3":
    print ""
    print "How do you do, player 3!"
    print ""
    Toon = "player 3" 
    sit1()

# introduction_paragraph is then supposed to be `print`ed with the avatar name. Instead, it `print`s only `""` However, if i have it `print` the current value for `Toon`, it spits out the intended value (I.E.: player 1, player 2, player 3)
def sit1():

    for introLine in introduction_paragraph:
        print introLine
    print ""
    print """ "So, how do you see yourself serving your country?" Commander Sheperd asks"""
#First Descision
    for sit1choice in sit1Choices:
        print ""
        print sit1choice
        print ""
    choice = raw_input("What do you say?")
    process(choice)
    print choice
    print Toon




#here's the code for the process(command) function, in case you're curious. 

def process(command):
    str(command)
    command.lower()
    if command == "help":
            print "To make a decision, just enter the corresponding number next to your choice"
            print "Type 'about' if you want to know who helped to make this project!"
            input()
    elif command == "about":
        for person in credits:
            print "%s : %s" % (person, credits[person])
    elif len(command) >= 1:
        return command
    else:
        print "%s is not a valid command" % command
        input()
def input():
    command = raw_input("What do you want to do?")
    process(command)
    return command

---

在设置Toon之前声明变量简介。因此，引言包含初始值，即

“

只需向下移动最后两行，直到Toon实际包含用户输入。将

Toon=“player X”

的每个实例替换为：

Toon = "player X"
introduction = """ "Hello %s, this is the US Military. You have been selected in the most recent draft as a candidate to serve your country. Please report to your nearest deafting outpost for your pre-enlistment interview, ASAP." [...] "Hello %s, I am Commander Sheperd. Please have a seat." """ % (Toon, Toon)
introduction_paragraph = textwrap.wrap(introduction, width = 70)

---

或者找到其他常见的时间点，您可以将名称添加到简介中，可能只是在它打印之前？

当您使用

%

操作符格式化

简介

字符串时，您正在将

卡通

的值与其当前值一起插入字符串中。如果以后更改

Toon

变量的值，

introduction

将不会更改以匹配它。如果要将名称的插入延迟到以后（当名称实际有意义时），则需要推迟格式设置。您仍然可以在顶部定义格式字符串

# start by defining the introduction string, with formatting codes, but no values yet
introduction = "Hello %s, this is the US Military..."

# later, assign Toon
Toon = "player 1"

# when you are ready to print the introduction, do the formatting:
print introduction % Toon

---

请注意，您可能希望使用较新样式的字符串格式，而不是带有

%

运算符的较旧样式。

在哪里定义了

sit1

？哦，我忘了添加它。很抱歉我把这两行移到了玩家选择头像之后，但是就在

for

循环打印段落之前，但是没有任何改变。我去了！只需将这两行移到sit1（）定义中即可。将这些行放在sit1（）定义之外的任何地方意味着该段落是在更新

toon

之前打印的。现在是凌晨4点。难怪我犯了这么简单的错误，代码学院课程中顺便提到了str.format方法。这门课没有讲。正因为如此，我坚持使用旧方法，直到我掌握了基本知识。

# start by defining the introduction string, with formatting codes, but no values yet
introduction = "Hello %s, this is the US Military..."

# later, assign Toon
Toon = "player 1"

# when you are ready to print the introduction, do the formatting:
print introduction % Toon