There is PEP 8, as other answers show, but PEP 8 is only the styleguide for the standard library, and it's only taken as gospel therein. One of the most frequent deviations of PEP 8 for other pieces of code is the variable naming, specifically for methods. There is no single predominate style, although considering the volume of code that uses mixedCase, if one were to make a strict census one would probably end up with a version of PEP 8 with mixedCase. There is little other deviation from PEP 8 that is quite as common.

就我个人而言，我尝试在类、mixedCase方法和函数中使用CamelCase。变量通常用下划线分隔(当我记得的时候)。这样我一眼就能知道我到底在调用什么，而不是所有东西看起来都一样。

无论是否在课堂上或在课堂外:

变量和函数小写，如下所示:

name = "John"

def display(name):
    print("John")

如果它们多于一个单词，则用下划线“_”分隔，如下所示:

first_name = "John"

def display_first_name(first_name):
    print(first_name)

并且，如果一个变量是一个常量，它是大写的，如下所示:

FIRST_NAME = "John"

我个人在用其他编程语言开发时使用Java的命名约定，因为它是一致的，易于遵循。这样我就不会一直纠结于使用什么约定，而这本来不应该是我项目中最难的部分!

@JohnTESlade的回答更进一步。谷歌的python风格指南有一些非常简洁的建议，

避免使用的名字

除计数器或迭代器外的单字符名称 在任何包/模块名称中使用破折号(-) \ __double_leading_and_trailing_下划线名称(由Python保留)

命名约定

"Internal" means internal to a module or protected or private within a class. Prepending a single underscore (_) has some support for protecting module variables and functions (not included with import * from). Prepending a double underscore (__) to an instance variable or method effectively serves to make the variable or method private to its class (using name mangling). Place related classes and top-level functions together in a module. Unlike Java, there is no need to limit yourself to one class per module. Use CapWords for class names, but lower_with_under.py for module names. Although there are many existing modules named CapWords.py, this is now discouraged because it's confusing when the module happens to be named after a class. ("wait -- did I write import StringIO or from StringIO import StringIO?")

指南源自圭多的建议

大多数使用python的人更喜欢下划线，但即使我已经使用python 5年多了，我仍然不喜欢它们。我只是觉得它们很丑，但也许这就是我脑子里的爪哇。

I simply like CamelCase better since it fits better with the way classes are named, It feels more logical to have SomeClass.doSomething() than SomeClass.do_something(). If you look around in the global module index in python, you will find both, which is due to the fact that it's a collection of libraries from various sources that grew overtime and not something that was developed by one company like Sun with strict coding rules. I would say the bottom line is: Use whatever you like better, it's just a question of personal taste.