Python之命令解析模块optparse

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()

增加选项(add_option())

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

定义短选项
parser.add_option(“-f”, attr=value, …)

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")

命令行格式可以有以下形式

-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()打印出来
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)

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

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)

提示结果如下

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.