允许值的 argparse 选择结构 [英] argparse choices structure of allowed values
问题描述
使用 argparse
与 组之间的 Python 依赖关系使用argparse,我有一个解析器的某个解析器组的参数部分 - 例如:
Using argparse
in relation to Python dependencies between groups using argparse, I have an argument part of some parser group of a parser - for example:
group_simulate.add_argument('-P',
help='simulate FC port down',
nargs=1,
metavar='fc_port_name',
dest='simulate')
如何使用选择来限制选择到下一个结构的参数列表:
How it's possible to use the choices to limit the choices to a list of parameters of the next structure:
1:m:"number between 1 and 10":p:"number between 1 and 4"
我尝试使用 range 选项,但找不到创建可接受的选项列表的方法
I have tried to use the range option but I couldn't find a way to create a list of choices that are acceptable
示例:合法参数:
test.py -P 1:m:4:p:2
不合法的参数:
test.py -P 1:p:2
test.py -P abvds
非常感谢大家的帮助!
推荐答案
您可以定义一个自定义类型,如果字符串与您需要的格式不匹配.
You can define a custom type that will raise an argparse.ArgumentTypeError
if the string
doesn't match the format you need.
def SpecialString(v):
fields = v.split(":")
# Raise a value error for any part of the string
# that doesn't match your specification. Make as many
# checks as you need. I've only included a couple here
# as examples.
if len(fields) != 5:
raise argparse.ArgumentTypeError("String must have 5 fields")
elif not (1 <= int(fields[2]) <= 10):
raise argparse.ArgumentTypeError("Field 3 must be between 1 and 10, inclusive")
else:
# If all the checks pass, just return the string as is
return v
group_simulate.add_argument('-P',
type=SpecialString,
help='simulate FC port down',
nargs=1,
metavar='fc_port_name',
dest='simulate')
更新:这里有一个完整的自定义类型来检查值.所有检查完成在正则表达式中,虽然它只给出一个通用的错误信息如果有任何部分错误.
UPDATE: here's a full custom type to check the value. All checking is done in the regular expression, although it only gives one generic error message if any part is wrong.
def SpecialString(v):
import re # Unless you've already imported re previously
try:
return re.match("^1:m:([1-9]|10):p:(1|2|3|4)$", v).group(0)
except:
raise argparse.ArgumentTypeError("String '%s' does not match required format"%(v,))
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