What are the ways to import modules in Python?

Python is a powerful programming language that allows you to organize code into reusable parts through the use of modules. A module is a file in a Python program that contains a set of related functions, classes, variables, etc. In Python, there are many ways to import modules. The following will introduce several common import methods and give corresponding code examples.

1. Directly import the entire module:
   This is the simplest way to import. You can import the entire module by using the import keyword followed by the module name. You can then use the functions, classes, variables, etc. in the module.
   For example, import the math module and use the sqrt function to calculate the square root:

import math

result = math.sqrt(16)
print(result)  # 输出4.0

2. Import specific functions, classes or variables in the module:
   Sometimes, just use Certain functions, classes or variables in the module can be imported using the from keyword.
   For example, import the sqrt function from the math module:

from math import sqrt

result = sqrt(16)
print(result)  # 输出4.0

3. Import the module and specify an alias for it:
   Sometimes, the module name is very long or conflicts, you can Imported modules are given aliases to make them easier to use.
   For example, import the numpy module and specify the alias np:

import numpy as np

arr = np.array([1, 2, 3, 4, 5])
print(arr)  # 输出[1, 2, 3, 4, 5]

4. Import multiple modules at once:
   If you need to import multiple modules, you can use one import statement Import simultaneously.
   For example, import the math and random modules:

import math, random

result = math.sqrt(random.randint(1, 100))
print(result)

5. Dynamic import module:
   Sometimes, you need to dynamically import modules based on some conditions or user selections. This can be achieved using the import_module function in the importlib module.
   For example, import the corresponding module based on user input:

import importlib

module_name = input("请输入模块名：")
module = importlib.import_module(module_name)

print(module.__name__)

The above are several commonly used module import methods in Python. Choosing the appropriate import method according to different needs can make the code more efficient. Flexible and maintainable. Through the import of modules, you can reuse the code you wrote, or use excellent modules written by others to improve development efficiency.

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