Introduction to Python functions: functions and usage examples of the vars function

Introduction to Python functions: functions and usage examples of the vars function

In Python programming, vars() is a very useful built-in function that returns an object's A dictionary of properties and values. This function can be used to obtain all properties and corresponding values ​​of an object, including variables, functions, classes, modules, etc.

The vars() function can accept one parameter, which is an object. If no parameters are passed in, the vars() function will return a dictionary of all global variables in the current scope. If a parameter is passed in, a dictionary of all attributes and corresponding values ​​of the object is returned.

The following is a simple example to show the use of vars() function:

class Person:
    def __init__(self, name, age):
        self.name = name
        self.age = age

person = Person("Alice", 30)
print(vars(person))

In this example, we define a Person class, which has two attributes: name and age . Then a Person object person is created and two parameters are passed in. Finally, by calling the vars() function, we can get the dictionary of attributes and corresponding values ​​of the person object. Running this code, the output is as follows:

{'name': 'Alice', 'age': 30}

In addition to objects, we can also use the vars() function to obtain the module's attributes and corresponding values. The following is an example:

import math
print(vars(math))

In this example, we imported Python's built-in math module and called the vars() function to obtain a dictionary of the module's attributes and corresponding values. Running this code, the output result is as follows:

{'__name__': 'math', '__doc__': 'This module provides access to the mathematical functions
defined by the C standard.', '__package__': 'math', '__loader__': <class '_frozen_importlib.BuiltinImporter'>, '__spec__': ModuleSpec(name='math', loader=<class '_frozen_importlib.BuiltinImporter'>), 'e': 2.718281828459045, 'pi': 3.141592653589793, ...}

By using the vars() function, we can obtain a dictionary of all attributes of the math module and corresponding values, including the ringing sand number e, pi, etc.

In addition to classes and modules, the vars() function can also be used inside functions. The following is an example:

def example_function():
    var1 = 1
    var2 = 2
    print(vars())

example_function()

In this example, we define a function named example_function(), which defines two variables var1 and var2 internally, and obtains the current value by calling the vars() function A dictionary of all variables in the scope and their corresponding values. Running this code, the output is as follows:

{'var1': 1, 'var2': 2}

By using the vars() function, we can obtain a dictionary of all variables and corresponding values ​​inside the function.

To summarize, the vars() function is a very convenient built-in function that is often used in Python programming. It can be used to obtain a dictionary of attributes and corresponding values ​​within objects, modules, and functions. By calling the vars() function, we can easily obtain all properties and corresponding values ​​of the object, and then operate and process them. At the same time, the vars() function can also help us understand the variables inside modules and functions, providing a convenient debugging tool.

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