An in-depth discussion of how to use Python command line parameters

Comprehensive analysis of Python command line parameters

When developing Python programs, we often need to obtain user-input parameters from the command line. Python provides many ways to handle command line parameters. This article will fully analyze these methods and give specific code examples.

1. sys.argv

sys.argv is a module in the Python standard library used to obtain command line parameters. It is a list containing all command line arguments, including the script name itself. The following is an example:

import sys

def main():
    # 获取命令行参数
    args = sys.argv

    # 打印脚本名称
    script_name = args[0]
    print("脚本名称：", script_name)

    # 打印其他参数
    for i, arg in enumerate(args[1:]):
        print("参数", i+1, "：", arg)

if __name__ == "__main__":
    main()

Assume the script name is example.py, run the command python example.py arg1 arg2 arg3, the output result is as follows:

脚本名称： example.py
参数 1 ： arg1
参数 2 ： arg2
参数 3 ： arg3

2. argparse module

argparse is another module in the Python standard library for handling command line arguments. Its function is more powerful and can define parameter types, default values, help information, etc. The following is an example:

import argparse

def main():
    # 创建解析器对象
    parser = argparse.ArgumentParser(description="这是一个示例程序")

    # 添加位置参数
    parser.add_argument("arg1", help="参数1的帮助信息")
    parser.add_argument("arg2", help="参数2的帮助信息")

    # 添加可选参数
    parser.add_argument("-v", "--verbose", action="store_true", help="启用详细输出")

    # 解析命令行参数
    args = parser.parse_args()

    # 输出参数值
    print("参数1：", args.arg1)
    print("参数2：", args.arg2)
    if args.verbose:
        print("详细输出已启用")

if __name__ == "__main__":
    main()

Assume the script name is example.py, run the command python example.py value1 value2 -v, the output result is as follows:

参数1： value1
参数2： value2
详细输出已启用

3. getopt module

Thegetopt module is another module in the Python standard library and is also used to handle command line parameters. Compared with argparse, its function is relatively simple, but more flexible. The following is an example:

import getopt
import sys

def main():
    # 定义短选项
    short_options = "hv"

    # 定义长选项
    long_options = ["help", "verbose"]

    try:
        # 解析命令行参数
        opts, args = getopt.getopt(sys.argv[1:], short_options, long_options)
    except getopt.GetoptError:
        # 处理参数错误
        print("参数错误")
        sys.exit(2)

    # 处理选项
    for opt, arg in opts:
        if opt in ("-h", "--help"):
            print("帮助信息")
        elif opt in ("-v", "--verbose"):
            print("详细输出已启用")

if __name__ == "__main__":
    main()

Assume that the script name is example.py, run the command python example.py -v, the output is as follows:

详细输出已启用

Whether using sys .argv, argparse or getopt, Python provides a variety of ways to process command line parameters. Developers can choose the appropriate method based on actual needs. I hope this article will help you understand Python command line parameters, and I hope you can flexibly use this knowledge to develop better Python programs.

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