Python 参数设置

1. 配置文件（ConfigParser模块）

1.1 ConfigParser简介

ConfigParser 是用来读取配置文件的包。配置文件的格式如下：中括号“[ ]”内包含的为section。section 下面为类似于key-value的options内容。例如

[db]
db_host = 127.0.0.1
db_port = 22
db_user = root
db_pass = rootroot
 
[concurrent]
thread = 10
processor = 20

 

1.2 ConfigParser 初始工作

使用ConfigParser 首选需要初始化实例，并读取配置文件：

import ConfigParser
cf = ConfigParser.ConfigParser()
cf.read("配置文件名")

 

1.3 ConfigParser函数

1.3.1. 获取所有sections

>>> s = cf.sections()
>>> print s
['db', 'concurrent']

1.3.2 获得指定section的options

>>> cf.options('db')
['db_host', 'db_port', 'db_user', 'db_pass']

1.3.3 获得指定sections的配置信息

>>> cf.items('db')
[('db_host', '127.0.0.1'), ('db_port', '22'), ('db_user', 'root'), ('db_pass', 'rootroot')]

1.3.4 获得指定sections的option的信息

>>> cf.get("db", "db_host")
'127.0.0.1'
>>> cf.getint("db", "db_port")
22

同样有getfloat、getboolean

以下注意：凡是改变文件内容的，都要最后写入。

1.3.5 设置某个option的值

>>> cf.set("db", "db_host", "127.1.1.1")
>>> cf.write(open("config.ini", 'w'))

写入后的文件内容为

[db]
db_host = 127.1.1.1
db_port = 22
db_user = root
db_pass = rootroot

[concurrent]
thread = 10
processor = 20

1.3.6 添加一个section

>>> cf.add_section("jihite")
>>> cf.set("jihite", "int", "15")
>>> cf.set("jihite", "bool", "True")
>>> cf.set("jihite", "float", "3.14")
>>> cf.write(open("config.ini", 'w'))

写入后的文件内容为

[db]
db_host = 127.1.1.1
db_port = 22
db_user = root
db_pass = rootroot

[concurrent]
thread = 10
processor = 20

[jihite]
int = 15
bool = True
float = 3.14

1.3.7 移除一个section

>>> cf.remove_option("jihite", "int")
True
>>> cf.write(open("config.ini", 'w'))

改变后的文件为

[db]
db_host = 127.1.1.1
db_port = 22
db_user = root
db_pass = rootroot

[concurrent]
thread = 10
processor = 20

[jihite]
bool = True
float = 3.14

1.3.8 移除一个option

>>> cf.remove_section("jihite")
True
>>> cf.write(open("config.ini", 'w'))

改变后的文件为

[db]
db_host = 127.1.1.1
db_port = 22
db_user = root
db_pass = rootroot

[concurrent]
thread = 10
processor = 20　　

1.4 ConfigParser举例

 

方式二：解析参数（argparse模块）

 

2. 解析参数（argparse模块）

2.1 argparse简介

argparse是python的命令行解析工具，它是Python标准库中推荐使用的编写命令行程序的工具。

 

2.2 argparser 初始工作

import argparse
parser = argparse.ArgumentParser()

类ArgumentParser定义为：

class ArgumentParser(prog=None, usage=None, description=None, epilog=None, parents=[], formatter_class=argparse.HelpFormatter, prefix_chars='-', fromfile_prefix_chars=None, argument_default=None, conflict_handler='error', add_help=True)

参数的含义为

2.2.1 prog:程序的名字，默认为sys.argv[0]　

>>> parser = argparse.ArgumentParser(prog="myprogram")
>>> parser.print_help()
usage: myprogram [-h]

optional arguments:
  -h, --help  show this help message and exit

2.2.2 usage: 描述程序用途的字符串

>>> parser = argparse.ArgumentParser(prog="myprogram", usage="%(prog)s [options]")
>>> parser.print_help()
usage: myprogram [options]

optional arguments:
  -h, --help  show this help message and exit

2.2.3 description: help信息前的文字

>>> parser.print_help()
usage: myprogram [options]

Create my own program

optional arguments:
  -h, --help  show this help message and exit

2.2.4 epilog:help之后的文字

>>> parser = argparse.ArgumentParser(prog="myprogram", usage="%(prog)s [options]", description="Create my own program", epilog="And that's how you'd foo a bar")

>>> parser.print_help()
usage: myprogram [options]

Create my own program

optional arguments:
  -h, --help  show this help message and exit

And that's how you'd foo a bar

2.2.5 　　

更详细参考

 

2.3 添加参数选项

http://www.cnblogs.com/linxiyue/p/3908623.html?utm_source=tuicool

 

3. 综合实例

要求

1. 配置文件和输入参数两种方式，其中输入参数优先级高

2. 参数包括配置文件、下载目录、进程个数、日志文件、日志类型

3. 如果进程个数不知，那么默认为机器cpu核数

4. 如果参数类型不知，那么默认为3

def setArgs():
    parse = argparse.ArgumentParser(prog = "down_v9.py", usage="%(prog)s [options]")
    parse.add_argument("-c", "-config", type=str, help="配置文件")
    parse.add_argument("-o", "-outdir", type=str, help="下载目录")
    parse.add_argument("-p", "-processnum", type=int, help="进程个数")
    parse.add_argument("-l", "-logfile", type=str, help="日志文件")
    parse.add_argument("-lt", "-logtype", type=str, help="输出日志类型：1，只显示到屏幕；2，只输出到日志文件；3，即显示到屏幕又输出到日志文件")
    args = parse.parse_args()
    return args

def get_args():
    args = setArgs()
    config = args.c
    outdir = args.o
    process_num = args.p
    logfile = args.l
    logtype = args.lt

    if config and os.path.isfile(config):
        cf = ConfigParser.ConfigParser()
        cf.read(config)
        s = cf.sections()
        if "con" in s:
            cons = cf.options("con")
            if outdir == None and "outdir" in cons:
                outdir = cf.get("con", "outdir")
            if process_num == None and "process_num" in cons:
                process_num = cf.getint("con", "process_num")
            if logfile == None and "logfile" in cons:
                logfile = cf.get("con", "logfile")
            if logtype == None and "logtype" in cons:
                logtype = cf.get("con", "logtype")
    if process_num == None:
        process_num = multiprocessing.cpu_count()
    if logtype == None:
        logtype = 3

    return [outdir, process_num, logfile, logtype]