search
HomeBackend DevelopmentPython TutorialPython中if __name__ == "__main__"详细解释

想必很多初次接触python都会见到这样一个语句,if __name__ == "__main__":

那么这个语句到底是做什么用的呢?在解释之前,首先要声明的是,不管你是多么小白,你一定要知道的是:

1.python文件的后缀为.py;

2..py文件既可以用来直接执行,就像一个小程序一样,也可以用来作为模块被导入(比如360安全卫士,就是依靠一个个功能模块来实现的,好比360安全卫士本身框架是一个桌面,而上面的图标就是快捷方式,这些快捷方式所指向的就是这一个个功能模块)

3.在python中导入模块一般使用的是import

好了,在确定知道以上几点之后,就可以开始解释if __name__ == "__main__":这个语句了。

首先解释一下if,顾名思义,if就是如果的意思,在句子开始处加上if,就说明,这个句子是一个条件语句。学习if语句的使用是很简单的,当然想要真正灵活运用还需大量的实践。

接着是 __name__,__name__作为模块的内置属性,简单点说呢,就是.py文件的调用方式。

最后是__main__,刚才我也提过,.py文件有两种使用方式:作为模块被调用和直接使用。如果它等于"__main__"就表示是直接执行。

总结:在if __name__ == "__main__":之后的语句作为模块被调用的时候,语句之后的代码不执行;直接使用的时候,语句之后的代码执行。通常,此语句用于模块测试中使用。

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
Is Tuple Comprehension possible in Python? If yes, how and if not why?Is Tuple Comprehension possible in Python? If yes, how and if not why?Apr 28, 2025 pm 04:34 PM

Article discusses impossibility of tuple comprehension in Python due to syntax ambiguity. Alternatives like using tuple() with generator expressions are suggested for creating tuples efficiently.(159 characters)

What are Modules and Packages in Python?What are Modules and Packages in Python?Apr 28, 2025 pm 04:33 PM

The article explains modules and packages in Python, their differences, and usage. Modules are single files, while packages are directories with an __init__.py file, organizing related modules hierarchically.

What is docstring in Python?What is docstring in Python?Apr 28, 2025 pm 04:30 PM

Article discusses docstrings in Python, their usage, and benefits. Main issue: importance of docstrings for code documentation and accessibility.

What is a lambda function?What is a lambda function?Apr 28, 2025 pm 04:28 PM

Article discusses lambda functions, their differences from regular functions, and their utility in programming scenarios. Not all languages support them.

What is a break, continue and pass in Python?What is a break, continue and pass in Python?Apr 28, 2025 pm 04:26 PM

Article discusses break, continue, and pass in Python, explaining their roles in controlling loop execution and program flow.

What is a pass in Python?What is a pass in Python?Apr 28, 2025 pm 04:25 PM

The article discusses the 'pass' statement in Python, a null operation used as a placeholder in code structures like functions and classes, allowing for future implementation without syntax errors.

Can we Pass a function as an argument in Python?Can we Pass a function as an argument in Python?Apr 28, 2025 pm 04:23 PM

Article discusses passing functions as arguments in Python, highlighting benefits like modularity and use cases such as sorting and decorators.

What is the difference between / and // in Python?What is the difference between / and // in Python?Apr 28, 2025 pm 04:21 PM

Article discusses / and // operators in Python: / for true division, // for floor division. Main issue is understanding their differences and use cases.Character count: 158

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

PhpStorm Mac version

PhpStorm Mac version

The latest (2018.2.1) professional PHP integrated development tool

SecLists

SecLists

SecLists is the ultimate security tester's companion. It is a collection of various types of lists that are frequently used during security assessments, all in one place. SecLists helps make security testing more efficient and productive by conveniently providing all the lists a security tester might need. List types include usernames, passwords, URLs, fuzzing payloads, sensitive data patterns, web shells, and more. The tester can simply pull this repository onto a new test machine and he will have access to every type of list he needs.

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!