python命令行参数模块optparse怎么用?

发布时间:2020-01-09编辑:脚本学堂
有关python命令行参数解析模块optparse的用法,包括增加选项(add_option())、行为(action)、设置默认值(default)、生成帮助提示(help)、设置boolean值、错误处理、选项组(grouping options)等。

python命令行参数解析模块optparse的用法

例子:
 

复制代码 代码示例:
from optparse import OptionParser
[...]
def main():
    usage = "usage: %prog [options] arg"
    parser = OptionParser(usage)
    parser.add_option("-f", "--file", dest="filename",
                      help="read data from FILENAME")
    parser.add_option("-v", "--verbose",
                      action="store_true", dest="verbose")
    parser.add_option("-q", "--quiet",
                      action="store_false", dest="verbose")
    [...]
    (options, args) = parser.parse_args()
    if len(args) != 1:
        parser.error("incorrect number of arguments")
    if options.verbose:
        print "reading %s..." % options.filename
    [...]
if __name__ == "__main__":
    main()

1、增加选项(add_option())
 

OptionParser.add_option(option)
OptionParser.add_option(*opt_str, attr=value, ...)

2、定义短选项
 

parser.add_option(“-f”, attr=value, …)

3、定义长选项
 

parser.add_option(“–foo”, attr=value, …)

如果定义:
 

parser.add_option("-f", "--file", action="store", type="string", dest="filename")

命令行格式的形式:
-ffoo
-f foo
--file=foo
--file foo

解析后结果:
 

options.filename = “foo”

解析(parse_args()):
 

(options, args) = parser.parse_args()

options 解析后的参数,以字典形式保存
args 不能解析的参数,以列表形式保存
行为(action)
●store 默认行为,保存值到dest
●“store_const” 保存常量
●“append” append this option's argument to a list
●“count” increment a counter by one
●“callback” call a specified function

设置默认值(default):
 

parser.add_option("-v", action="store_true", dest="verbose", default=True)
parser.set_defaults(verbose=True)

生成帮助提示(help)
提供help选项即可,可以用parser.print_help()打印:
 

parser.add_option(“-f”, “–file”, dest=”filename”,help=”write report to FILE”, metavar=”FILE”)

设置boolean值
支持store_true和store_false两个行为:
 

parser.add_option("-v", action="store_true", dest="verbose")
parser.add_option("-q", action="store_false", dest="verbose")

如果遇到-v,verbose=True;如果遇到-q,verbose=False
错误处理:
 

(options, args) = parser.parse_args()
[...]
if options.a and options.b:
    parser.error("options -a and -b are mutually exclusive")

选项组(Grouping Options)
格式:
 

class optparse.OptionGroup(parser, title, description=None)

例子:
 

复制代码 代码示例:
group = OptionGroup(parser, "Dangerous Options",
                    "Caution: use these options at your own risk.  "
                    "It is believed that some of them bite.")
group.add_option("-g", action="store_true", help="Group option.")
parser.add_option_group(group)

输出结果:
Usage: <yourscript> [options] arg1 arg2
Options:
  -h, --help            show this help message and exit
  -v, --verbose         make lots of noise [default]
  -q, --quiet           be vewwy quiet (I'm hunting wabbits)
  -f FILE, --filename=FILE
                        write output to FILE
  -m MODE, --mode=MODE  interaction mode: novice, intermediate, or
                        expert [default: intermediate]
  Dangerous Options:
    Caution: use these options at your own risk.  It is believed that some
    of them bite.
    -g                  Group option.