SoFunction
Updated on 2025-05-07

Specific use of variables starting with _ in Python

1. Preface

I've seen a lot of interesting things recentlyPython moduleCode in  such as

def get_key():
    _ = load_dotenv(find_dotenv())
    return ['KEY']

In such as:

_rag_query_text = ""

Very curious, ordinaryPython moduleThe code in it is notPython Class, _ What exactly does it mean?

2. Explore the role of python_variables

In Python, underline with single_The name that begins (such as a variable, function, or class) is called the "single underscore" name. They have some special meanings and uses, following some practices and guidelines.

  • Private Members: In a class or module, names starting with a single underscore are consideredprivate(private). This is a naming convention designed to prevent accidental overwriting or access to these names. However, Python does not enforce this convention, it is just aAgree, aimed atRemind other programmers not to use these variables directly in other code
  • Avoid conflicts with Python keywords and built-in functions: By adding a single underscore before the variable name, conflicts with Python keywords and built-in functions can be avoided. For example, you can use_printAs a variable name, not with built-in functionsprint()Conflict.
  • Temporary or irrelevant variables: Single underscore is often used to represent temporary or insignificant variables.Used to represent a value that does not need to be used, for example, in a loop_As a counter variable. like:
for _ in range(5):
    # Perform some operations without using the value of the iterative variable    do_something()

Special variable name: Python also has some special single underscore names that have specific meanings and uses:

  • _(Single Underscore): Indicates the previous result in the interpreter.
  • __name__: The name of the current module, if it is the main program, it is"__main__"。
  • __main__: Used as a program entry point.

In general, names starting with a single underscore are primarily a naming convention that indicates that the name has a special purpose or private nature. However, Python does not enforce this convention, it is just a convention and practice.

3. Summary

This article discusses the uses and meaning of variables starting with a single underscore in Python. These variables can be used as private members, avoid conflicts with keywords and built-in functions, represent temporary or inconsequential variables, and represent special variable names. Although these conventions are not enforceable, they help improve the readability and maintainability of the code. Following these conventions when writing Python code can help developers better understand and use variables.

This is the introduction to this article about the specific use of variables at the beginning in Python. For more related variables at the beginning, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!