第2单 2.2 准备一项任务

一、普通接收参数

import argparse

def main(number, other_number):
    result = number * other_number
    print(f'The result is {result}')

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('-n1', type=int, help='A number', default=1)
    parser.add_argument('-n2', type=int, help='Another number', default=1)

    args = parser.parse_args()

    main(args.n1, args.n2)

　　

(.venv) huangsiyangdeiMac:ch02 huangsiyang$ python prepare_task_step1.py 

The result is 1

(.venv) huangsiyangdeiMac:ch02 huangsiyang$ python prepare_task_step1.py -n1 3 -n2 4

The result is 12

 

二、读取配置文件：

import argparse 
import configparser

def main(number, other_number):
    result = number * other_number
    print(f'The result is {result}')

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('-n1', type=int, help='A number', default=1)
    parser.add_argument('-n2', type=int, help='Another numnber', default=1)

    parser.add_argument('--config', '-c', type=argparse.FileType('r'), 
                        help='config file')

    args = parser.parse_args()

    if args.config:
        config = configparser.ConfigParser()
        config.read_file(args.config)
        # Transforming values into integers
        args.n1 = int(config['ARGUMENTS']['n1'])
        args.n2 = int(config['ARGUMENTS']['n2'])

    main(args.n1, args.n2)

　

配置文件的内容config.ini：

[ARGUMENTS]

n1=5

n2=7

执行结果如下：

(.venv) huangsiyangdeiMac:ch02 huangsiyang$ python prepare_task_step2.py -c config.ini

The result is 35

(.venv) huangsiyangdeiMac:ch02 huangsiyang$ python prepare_task_step2.py -c config.ini -n1 2 -n2 3

The result is 35

#配置文件的值会覆盖传入参数的值。

三、将执行结果输出到文件：

import argparse
import sys
import configparser

def main(number, other_number, output):
    result = number * other_number
    print(f'The result is {result}', file=output)

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('-n1', type=int, help='A number', default=1)
    parser.add_argument('-n2', type=int, help='Another number', default=1)
    parser.add_argument('--config', '-c', type=argparse.FileType('r'), 
                        help = 'config file')
    parser.add_argument('-o', dest='output', type=argparse.FileType('w'), 
                        help = 'output file', default=sys.stdout)

    args = parser.parse_args()
    if args.config:
        config = configparser.ConfigParser()
        config.read_file(args.config)
        # Transforming values into integers
        args.n1 = int(config['ARGUMENTS']['n1'])
        args.n2 = int(config['ARGUMENTS']['n2'])

    main(args.n1, args.n2, args.output)

　　

(.venv) huangsiyangdeiMac:ch02 huangsiyang$ python prepare_task_step5.py -n1 3 -n2 5 

The result is 15

(.venv) huangsiyangdeiMac:ch02 huangsiyang$ python prepare_task_step5.py -n1 3 -n2 5  -o result.txt

(.venv) huangsiyangdeiMac:ch02 huangsiyang$ cat result.txt 

The result is 15

(.venv) huangsiyangdeiMac:ch02 huangsiyang$ python prepare_task_step5.py -c config.ini -o result2.txt

(.venv) huangsiyangdeiMac:ch02 huangsiyang$ cat result2.txt 

The result is 35

#将结果输出到文件

 

四、通过使用YAML文件作为配置：

首先安装支持YAML的库:

(.venv) huangsiyangdeiMac:ch02 huangsiyang$ echo 'PyYAML==3.12' > requirements.txt

(.venv) huangsiyangdeiMac:ch02 huangsiyang$ pip3 install -r requirements.txt 

Collecting PyYAML==3.12

  Downloading PyYAML-3.12.zip (375 kB)

     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 375.8/375.8 KB 1.1 MB/s eta 0:00:00

  Preparing metadata (setup.py) ... done

Using legacy 'setup.py install' for PyYAML, since package 'wheel' is not installed.

Installing collected packages: PyYAML

  Running setup.py install for PyYAML ... done

Successfully installed PyYAML-3.12

 

import yaml
import argparse
import sys

def main(number, other_number, output):
    result = number * other_number
    print(f'The result is {result}', file=output)

if __name__ == '__main__':
    parser = argparse.ArgumentParser()
    parser.add_argument('-n1', type=int, help='A number', default=1)
    parser.add_argument('-n2', type=int, help='Another number', default=1)

    parser.add_argument('-c', dest='config', type=argparse.FileType('r'), 
                        help='config file in YAML format', default=None)
    parser.add_argument('-o', dest='output', type=argparse.FileType('w'),
                        help='output file', default=sys.stdout)

    args = parser.parse_args()
    if args.config:
        config = yaml.load(args.config)
        # No need to transform values
        args.n1 = config['ARGUMENTS']['n1']
        args.n2 = config['ARGUMENTS']['n2']

    main(args.n1, args.n2, args.output)

　　

(.venv) huangsiyangdeiMac:ch02 huangsiyang$ cat config.yaml 

ARGUMENTS:

    n1: 7

    n2: 4

 

(.venv) huangsiyangdeiMac:ch02 huangsiyang$ python prepare_task_yaml.py -c config.yaml 

The result is 28