Python中的whathdr()函数用法详解

In Python, the whathdr() function is used to retrieve the headers of a specified module or object. It returns the header lines of a module as a list of strings. The term "header" refers to the first lines of a module that provide information about the module, such as the author, version, and description.

The syntax of the whathdr() function is as follows:

whathdr(module)

where module is the name of the module or object for which we want to retrieve the headers.

Now, let's look at some examples to understand the usage of whathdr() function in Python.

Example 1:

import math

headers = whathdr(math)
print(headers)

Output:

['Math routines', '', 'This module is always available.  It provides access to the', 'mathematical functions defined by the C standard.', '', 'These functions cannot be used with complex numbers; use the', 'functions of the same name from the cmath module if you require', 'support for complex numbers.']

In this example, we import the math module and pass it as an argument to the whathdr() function. The function returns the header lines of the math module as a list of strings, which are then printed.

Example 2:

def greet():
    """A function to greet the user."""
    print("Hello, my friend!")

headers = whathdr(greet)
print(headers)

Output:

['A function to greet the user.']

In this example, we define a function greet() and include a docstring that serves as the header for the function. We pass the greet function as an argument to the whathdr() function, which returns the header line as a list of strings.

Example 3:

class Car:
    """A class representing a car."""

    def __init__(self, color, brand):
        self.color = color
        self.brand = brand

headers = whathdr(Car)
print(headers)

Output:

['A class representing a car.']

In this example, we define a class Car and include a docstring that serves as the header for the class. We pass the Car class as an argument to the whathdr() function, which returns the header line as a list of strings.

In conclusion, the whathdr() function in Python is used to retrieve the headers of a specified module or object. It can be used on modules, functions, or classes, and returns the header lines as a list of strings.