In-depth analysis of Python command line parameters and application examples

Detailed explanation of Python command line parameters and example applications

In Python programming, we often need to obtain parameters from the command line to perform different operations. Python has a built-in argparse module that can help us parse command line parameters and perform different logic based on the parameters. This article will introduce the usage of the argparse module in detail and give some code examples of practical applications.

1. Introduction to argparse module

The argparse module is a command line parameter parsing module in the Python standard library. It can help us parse command line parameters, provide friendly help information, and type examine. It can automatically generate a parameter parser, we only need to define the required parameters. The following is a simple example:

import argparse

parser = argparse.ArgumentParser(description='这是一个命令行参数示例程序')
parser.add_argument('-n', '--name', required=True, help='输入姓名')
parser.add_argument('-a', '--age', required=True, type=int, help='输入年龄')

args = parser.parse_args()

print('姓名：', args.name)
print('年龄：', args.age)

In the above example, we defined two parameters: name and age. Among them, the name parameter has an abbreviated form -n, and the age parameter has an abbreviated form -a. Both the name parameter and the age parameter are marked as required parameters (required=True), and both have a help message.

A parameter parser parser is defined through the ArgumentParser class of the argparse module, and a description string is passed in. Then, we added two parameters through the parser.add_argument() method, corresponding to name and age. In the definition of parameters, we can specify the abbreviated form of the parameter (such as -n), or the full form of the parameter (such as --name), and we can specify the type of the parameter. Finally, we parse the command line parameters through the parser.parse_args() method, and the parsing results are saved in the args variable.

2. Code Examples

Below we give several specific application code examples:

1. Calculate the sum of two numbers

import argparse

parser = argparse.ArgumentParser(description='计算两个数的和')
parser.add_argument('-a', '--a', required=True, type=float, help='输入第一个数')
parser.add_argument('-b', '--b', required=True, type=float, help='输入第二个数')

args = parser.parse_args()

result = args.a + args.b

print('结果：', result)

In this example, we define two parameters a and b, which represent two numbers respectively. Then, we reference these two parameters through args.a and args.b, and calculate the result.

2. Find files

import argparse
import os

parser = argparse.ArgumentParser(description='查找文件')
parser.add_argument('-p', '--path', required=True, help='输入需要查找的路径')
parser.add_argument('-e', '--extension', required=True, help='输入文件的扩展名')

args = parser.parse_args()

def find_files(path, extension):
    result = []
    for root, dirs, files in os.walk(path):
        for file in files:
            if file.endswith(extension):
                result.append(os.path.join(root, file))
    return result

files = find_files(args.path, args.extension)

print('文件列表：')
for file in files:
    print(file)

In this example, we define two parameters path and extension, which respectively represent the path to be searched and the extension of the file. Then, we reference these two parameters through args.path and args.extension, and call the find_files() function to find files that meet the conditions.

3. Summary

The argparse module is a very useful module in Python programming. It can help us parse command line parameters and execute different logic based on the parameters. This article introduces the usage of the argparse module and gives some code examples of practical applications. I hope readers can gain an in-depth understanding of the argparse module through this article and be able to use it flexibly in actual development.

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