我们的一些生物技术客户最近提出了这两个问题:

如何将Python脚本作为命令执行? 当Python脚本作为命令执行时，我们如何将输入值传递给它?

我在下面附上了一个Python脚本，我相信它可以回答这两个问题。让我们假设下面的Python脚本保存在test.py文件中:

#
#----------------------------------------------------------------------
#
# file name: test.py
#
# input values: data  - location of data to be processed
#               date  - date data were delivered for processing
#               study - name of the study where data originated
#               logs  - location where log files should be written 
#
# macOS usage: 
#
#   python3 test.py "/Users/lawrence/data" "20220518" "XYZ123" "/Users/lawrence/logs"
#
# Windows usage: 
#
#   python test.py "D:\data" "20220518" "XYZ123" "D:\logs"
#
#----------------------------------------------------------------------
#
# import needed modules...
#
import sys
import datetime

def main(argv):

   #
   # print message that process is starting...
   #
   print("test process starting at", datetime.datetime.now().strftime("%Y%m%d %H:%M"))

   #
   # set local values from input values...
   #
   data = sys.argv[1]
   date = sys.argv[2]
   study = sys.argv[3]
   logs = sys.argv[4]

   #
   # print input arguments...
   #
   print("data value is", data)
   print("date value is", date)
   print("study value is", study)
   print("logs value is", logs)

   #
   # print message that process is ending...
   #
   print("test process ending at", datetime.datetime.now().strftime("%Y%m%d %H:%M"))

#
# call main() to begin processing...
#

if __name__ == '__main__':

   main(sys.argv)

该脚本可以在macOS计算机上的Terminal shell中执行，如下所示，结果将被打印到标准输出(确保当前目录包括test.py文件):

$ python3 test.py "/Users/lawrence/data" "20220518" "XYZ123" "/Users/lawrence/logs"
test process starting at 20220518 16:51
data value is /Users/lawrence/data
date value is 20220518
study value is XYZ123
logs value is /Users/lawrence/logs
test process ending at 20220518 16:51

该脚本也可以在Windows计算机上的命令提示符中执行，如下所示，结果将被打印到标准输出(确保当前目录包括test.py文件):

D:\scripts>python test.py "D:\data" "20220518" "XYZ123" "D:\logs"
test process starting at 20220518 17:20
data value is D:\data
date value is 20220518
study value is XYZ123
logs value is D:\logs
test process ending at 20220518 17:20

这个脚本回答了上面提出的两个问题，并且是开发将作为带有输入值的命令执行的脚本的一个很好的起点。

docopt库非常漂亮。它为你的应用程序从usage字符串中构建一个参数dict。

来自docopt自述文件:

"""Naval Fate.

Usage:
  naval_fate.py ship new <name>...
  naval_fate.py ship <name> move <x> <y> [--speed=<kn>]
  naval_fate.py ship shoot <x> <y>
  naval_fate.py mine (set|remove) <x> <y> [--moored | --drifting]
  naval_fate.py (-h | --help)
  naval_fate.py --version

Options:
  -h --help     Show this screen.
  --version     Show version.
  --speed=<kn>  Speed in knots [default: 10].
  --moored      Moored (anchored) mine.
  --drifting    Drifting mine.

"""
from docopt import docopt


if __name__ == '__main__':
    arguments = docopt(__doc__, version='Naval Fate 2.0')
    print(arguments)

import sys

print("\n".join(sys.argv))

sys。Argv是一个列表，它包含在命令行上传递给脚本的所有参数。sys。Argv[0]为脚本名称。

基本上,

import sys
print(sys.argv[1:])

import sys

# Command line arguments are stored into sys.argv
# print(sys.argv[1:])

# I used the slice [1:] to print all the elements except the first
# This because the first element of sys.argv is the program name
# So the first argument is sys.argv[1], the second is sys.argv[2] ecc

print("File name: " + sys.argv[0])
print("Arguments:")
for i in sys.argv[1:]:
    print(i)

让我们把这个文件命名为command_line.py，然后运行它:

C:\Users\simone> python command_line.py arg1 arg2 arg3 ecc
File name: command_line.py
Arguments:
arg1
arg2
arg3
ecc

现在让我们写一个简单的程序sum.py:

import sys

try:
    print(sum(map(float, sys.argv[1:])))
except:
    print("An error has occurred")

结果:

C:\Users\simone> python sum.py 10 4 6 3
23

import argparse

parser = argparse.ArgumentParser(description='Process some integers.')
parser.add_argument('integers', metavar='N', type=int, nargs='+',
                   help='an integer for the accumulator')
parser.add_argument('--sum', dest='accumulate', action='store_const',
                   const=sum, default=max,
                   help='sum the integers (default: find the max)')

args = parser.parse_args()
print(args.accumulate(args.integers))

Assuming the Python code above is saved into a file called prog.py
$ python prog.py -h

Ref-link: https://docs.python.org/3.3/library/argparse.html

我喜欢从stdlib中获取getopt，例如:

try:
    opts, args = getopt.getopt(sys.argv[1:], 'h', ['help'])
except getopt.GetoptError, err: 
    usage(err)

for opt, arg in opts:
    if opt in ('-h', '--help'): 
        usage()

if len(args) != 1:
    usage("specify thing...")

最近，我一直在包装类似的东西，使事情更少的啰嗦(例如;使“-h”隐式)。