2025py重学计划

Day 1

写一个 CLI 工具，输入姓名打印问候语

v1 cat  echo.py 
name = 'evan'
print( name + "  have a good day")

v2
➜  py2025 cat echo.py 
name = input("please input your name")
print( name + "  have a good day")

 py  echo.py 
please input your name evan
 evan  have a good day
➜  py2025 cat echo.py 


v3
import sys
if  len(sys.argv) < 2:
    print("Usage: python echo.py <name>")
else:
    name = sys.argv[1]
    print(f"Hi,  {name}    have a good day")

➜  py2025 py  echo.py 
Usage: python echo.py <name>
➜  py2025 py  echo.py  evan
Hi,  evan    have a good d

v4 
➜  py2025 cat greet.py 
import argparse 
def main():
    parser = argparse.ArgumentParser(description="Say Hi to someone")
    parser.add_argument("-n","--name",required=True,help="The name of the person to greet.")
    args = parser.parse_args()
    print(f"Hello,{args.name} hope you have a  good day")

if __name__ == "__main__":
    main()


➜  py2025 python greet.py -n evan 
Hello,evan hope you have a  good day