Argparse，处理可重复的项集。-Argparse,handlerepeatablesetofitems

2  

A way to make arguments repeatable is to use an 'append' action type:

使参数可重复的一种方法是使用“append”操作类型:

import argparse
parser = argparse.ArgumentParser()
parser.add_argument('-a', action='append')
parser.add_argument('-b', action='append')
parser.add_argument('-c', action='append')
argv = '-a 1 -b 2 -c 3    -a 4 -c 6   -a 7 -b 8    -a 10'
args = parser.parse_args(argv.split())
print args

produces:

生产:

Namespace(a=['1', '4', '7', '10'], b=['2', '8'], c=['3', '6'])

Unfortunately it does lose some information. There's no way to associate the '4' with the '6' instead of the '8'.

不幸的是，它确实丢失了一些信息。没有办法把“4”和“6”联系起来，而不是“8”。

If you use '--' to separate blocks of arguments, then this iterative parser might do the job:

如果您使用“—”来分隔参数块，那么这个迭代解析器可能会完成任务:

parser = argparse.ArgumentParser()
# SUPPRESS keeps the default None out of the namespace
parser.add_argument('-a', type=int, default=argparse.SUPPRESS, required=True)
parser.add_argument('-b', type=int, default=argparse.SUPPRESS)
parser.add_argument('-c', type=int, default=argparse.SUPPRESS)
argv = '-a 1 -b 2 -c 3  --  -a 4 -c 6 --  -a 7 -b 8  --  -a 10'

arglist = []
rest = argv.split()
while rest:
    args,rest = parser.parse_known_args(rest)
    rest = rest[1:]  # remove the 1st '--'
    print args
    arglist.append(vars(args))
print arglist

producing:

生产:

Namespace(a=1, b=2, c=3)
Namespace(a=4, c=6)
Namespace(a=7, b=8)
Namespace(a=10)

[{'a': 1, 'c': 3, 'b': 2}, 
 {'a': 4, 'c': 6}, 
 {'a': 7, 'b': 8}, 
 {'a': 10}]

I'm not sure if it is robust enough. I made -a required, so omitting it from one of the groups will raise an error.

我不确定它是否足够坚固。我做了一个要求，所以从其中一个组省略它会引起错误。

Or adapting farzad's iterator:

或适应法扎德的迭代器:

def by_sets(iterator, start):
    set = []
    for val in iterator:
        if set and val == start:
            yield set
            set = [val]
        else:
            set.append(val)
    yield set

argv = '-a 1 -b 2 -c 3  -a 4 -c 6 -a 7 -b 8  -a 10'
# print list(by_sets(argv.split(), '-a'))
# [['-a', '1', '-b', '2', '-c', '3'], ['-a', '4', '-c', '6'],... ['-a', '10']]

arglist = []
for aset in by_sets(argv.split(), '-a'):
    arglist.append(vars(parser.parse_args(aset)))
print arglist

produces:

生产:

[{'a': 1, 'c': 3, 'b': 2}, {'a': 4, 'c': 6}, {'a': 7, 'b': 8}, {'a': 10}]

The loop can also be written as a comprehension:

这个循环也可以写成理解:

[vars(parser.parse_args(aset)) for aset in by_sets(argv.split(), '-a')]

1  

We could iterate over command line args and add them one by one to the set, if we reached to '-a' which marks the start of another set, we'll create a new set. This code sample does not check for invalid user input though.

我们可以遍历命令行args，并将它们逐一添加到集合中，如果我们到达“-a”，这标志着另一个集合的开始，我们将创建一个新的集合。

import sys

def get_pairs(iterator, start):
    sets = []
    for val in iterator:
        if val == start:
            sets.append({})
        sets[-1][val] = next(iterator)
    return sets

print get_pairs(iter(sys.argv[1:]), '-a')