遍历嵌套列表和字典 [英] Iterate over nested lists and dictionaries

问题描述

我需要遍历嵌套列表和字典，并用十六进制字符串替换每个整数.例如，这样的元素可能看起来像这样:

I need to iterate over nested lists and dictionaries and replace every integer trough an hex string. Such an element could for example look like this:

element = {'Request': [16, 2], 'Params': ['Typetext', [16, 2], 2], 'Service': 'Servicetext', 'Responses': [{'State': 'Positive', 'PDU': [80, 2, 0]}, {}]}

应用该函数后，它应如下所示:

After after applying the function, it should look like this:

element = {'Request': ['0x10', '0x02'], 'Params': ['Typetext', ['0x10', '0x02'], '0x02'], 'Service': 'Servicetext', 'Responses': [{'State': 'Positive', 'PDU': ['0x50', '0x02', '0x00']}, {}]}

我已经找到了一个函数，可以对这样的嵌套可迭代对象进行迭代 http://code.activestate.com/recipes/577982-recursively-walk-python-objects/.适应python 2.5时，此函数如下所示:

I've already found a function, to iterate over such nested iterables http://code.activestate.com/recipes/577982-recursively-walk-python-objects/. Adapted to python 2.5 this function looks like this:

string_types = (str, unicode)
iteritems = lambda mapping: getattr(mapping, 'iteritems', mapping.items)()

def objwalk(obj, path=(), memo=None):
    if memo is None:
        memo = set()
    iterator = None
    if isinstance(obj, dict):
        iterator = iteritems
    elif isinstance(obj, (list, set)) and not isinstance(obj, string_types):
        iterator = enumerate
    if iterator:
        if id(obj) not in memo:
            memo.add(id(obj))
            for path_component, value in iterator(obj):
                for result in objwalk(value, path + (path_component,), memo):
                    yield result
            memo.remove(id(obj))
    else:
        yield path, obj

但是此函数的问题在于，它返回元组元素.并且那些不能被编辑. 您能帮我实现我需要的功能吗?

But the problem with this function is, that it returns tuple elements. And those can't be edited. Can you help me to implement a function I need?

最诚挚的问候 威瓦

推荐答案

该函数不仅返回元组元素，还返回元组元素.它返回嵌套结构中任何项目的路径及其值.您可以使用该路径获取值并对其进行更改:

The function doesn't just return tuple elements; it returns the path to any item in the nested structure, plus it's value. You can use that path to get at the value and change it:

for path, value in objwalk(element):
    if isinstance(value, int):
        parent = element
        for step in path[:-1]:
            parent = parent[step]
        parent[path[-1]] = hex(value)

因此，对于每个整数值，请使用路径查找该值的父级，然后将其替换为十六进制等效值.

So, for every value that is an integer, use the path to find the parent of that value, then replace the current value with it's hex equivalent.

您从上述方法获得的输出:

The output you get from the above method:

>>> element
{'Params': ['Typetext', ['0x10', '0x2'], '0x2'], 'Request': ['0x10', '0x2'], 'Responses': [{'State': 'Positive', 'PDU': ['0x50', '0x2', '0x0']}, {}], 'Service': 'Servicetext'}

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