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_host = 127.0.0.1
db_port = 22
db_user = root
db_pass = rootroot
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_host = 127.1.1.1
db_port = 22
db_user = root
db_pass = rootroot
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_host = 127.1.1.1
db_port = 22
db_user = root
db_pass = rootroot
thread = 10
processor = 20
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_host = 127.1.1.1
db_port = 22
db_user = root
db_pass = rootroot
thread = 10
processor = 20
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_host = 127.1.1.1
db_port = 22
db_user = root
db_pass = rootroot
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
>>> parser = argparse.ArgumentParser(prog="myprogram")
>>> parser.print_help()
usage: myprogram [-h]
optional arguments:
-h, --helpshow 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 ")
>>> parser.print_help()
usage: myprogram
optional arguments:
-h, --helpshow this help message and exit
2.2.3 description: help信息前的文字
>>> parser.print_help()
usage: myprogram
Create my own program
optional arguments:
-h, --helpshow this help message and exit
2.2.4 epilog:help之后的文字
>>> parser = argparse.ArgumentParser(prog="myprogram", usage="%(prog)s ", description="Create my own program", epilog="And that's how you'd foo a bar")
>>> parser.print_help()
usage: myprogram
Create my own program
optional arguments:
-h, --helpshow 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 ")
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
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