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使用Python 3试图通过寻找特定的字符和判断在哪里单独
所以基本上我有一段代码，试图看一个文本文件，看起来比符号的少单独的线。如果在它之后发现一个大于号的符号，然后是一个大写字母，它就知道它是一个新行的开始，所以它在那里放置一个\n。我遇到了“局部变量”错误，但我不知道为什么。它不应该发生，因为我在函数中使用变量而不使用任何全局变量。奇怪的是，代码适用于“独立”函数的前三个调用，但不适用于第四个调用。我唯一的解释是，while (example[x] != "<"):循环根本不在任何原因的第四次“分离”函数调用中执行。
example = "Tags for HTML: <!--...--> Defines a comment <!DOCTYPE> Defines the document
type <a> Defines a hyperlink <abbr> Defines an abbreviation or an acronym <acronym> Not
supported in HTML5. Use <abbr> instead. Defines an acronym <address> Defines contact
information for the author/owner of a document <applet> Not supported in HTML5. Use
<embed> or <object> instead. Defines an embedded applet <area> Defines an area inside
an image-map <article> Defines an article <aside> Defines content aside from the page
content <audio> Defines sound content <b> Defines bold text"
x = 0
def separate(x, example):
f=open('format_output.txt','w')
#looking for the first less than sign
while (example[x] != "<"):
x+=1
#advancing and storing the lineholder so it can enter a newline when done
lineholder = x
#looking for the first greater than sign
while (example[x] != ">"):
#advancing the cursor
x+=1
#checking if the position two characters from the cursor is an uppercase letter
this = example[x+2:x+3]
if(this.isupper()):
#if it is, print "it's upper"
print("its upper")
#putting everything before lineholder into a variable
temp_file_string = example[:lineholder]
#adding a newline to it
temp_file_string = temp_file_string + "\r\n"
#putting everything after linholder into another variable
rest_of_string = example[lineholder:]
#writing them combined into the output file
f.write(temp_file_string + rest_of_string)
#rewinding the file cursor so the file can be read and printed to the shell
f.seek(0)
f=open('format_output.txt','r')
example = f.read()
print("\n\nprinting contents:\n\n" + example)
f.close
return (x, example)
else:
#else say 'Isn't Uppper'
lineholder = x
print("Isn't Upper")
return (x , example)
(x, example) = separate(x, example)
(x, example) = separate(x, example)
(x, example) = separate(x, example)
(x, example) = separate(x, example)
print('\n'+str(x))
该错误消息指出：
local variable 'lineholder' referenced before assignment
在线：
temp_file_string = example[:lineholder]
我使用的功能四次连续仅仅是为了测试代码。我希望能够简单地循环该函数，并自动处理“示例”，并在每个标记完成描述之后放置一个换行符。
输出应该是：
Tags for HTML:
<!--...--> Defines a comment
<!DOCTYPE> Defines the document type
<a> Defines a hyperlink
<abbr> Defines an abbreviation or an acronym
<acronym> Not supported in HTML5. Use <abbr> instead. Defines an acronym
<address> Defines contact information for the author/owner of a document
<applet> Not supported in HTML5. Use <embed> or <object> instead. Defines an embedded applet
<area> Defines an area inside an image-map
<article> Defines an article
<aside> Defines content aside from the page content
<audio> Defines sound content
<b> Defines bold text
我是相当新的Python和一般的编码，所以我知道我的代码是非常糟糕和混乱。我知道我在这里犯了严重的错误，所以请纠正我。