迭代嵌套列表,元组和字典

时间:2012-07-16 13:24:11

标签: python loops

我对Iterate over nested lists and dictionaries的主题提出了另一个问题。

我需要一些上述链接主题的扩展功能。可迭代元素现在还包含元组。元组中的整数也需要转换为十六进制字符串。因此,我尝试使用以下代码将元组转换为列表。

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

但我的问题是,元组中的元组没有被转换。如何以优雅的方式将“子元组”转换为列表?

祝你好运 wewa

PS:我创建了一个新主题,因为另一个是为我修复的。

2 个答案:

答案 0 :(得分:1)

在这种情况下,直接在objwalk结构遍历器中处理元组会更容易。这是一个修改后的版本,它在遍历它们以查找嵌套元素之前将元组转换为列表:

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):
                if isinstance(value, tuple):
                    obj[path_component] = value = list(value)
                for result in objwalk(value, path + (path_component,), memo):
                    yield result
            memo.remove(id(obj))
    else:
        yield path, obj

使用上一个问题中稍加修改的示例,以及我在该问题中提供的相同hex解决方案:

>>> element = {'Request': (16, 2), 'Params': ('Typetext', [16, 2], 2), 'Service': 'Servicetext', 'Responses': ({'State': 'Positive', 'PDU': [80, 2, 0]}, {})}
>>> 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)
... 
>>> element
{'Params': ['Typetext', ['0x10', '0x2'], '0x2'], 'Request': ['0x10', '0x2'], 'Responses': [{'State': 'Positive', 'PDU': ['0x50', '0x2', '0x0']}, {}], 'Service': 'Servicetext'}

答案 1 :(得分:1)

如果创建新对象的开销不是问题,我认为很清楚:

def transform(obj):
    _type = type(obj)
    if _type == tuple: _type = list
    rslt = _type()
    if isinstance(obj, dict):
        for k, v in obj.iteritems():
            rslt[k] = transform(v)
    elif isinstance(obj, (list, tuple)):
        for x in obj:
            rslt.append(transform(x))
    elif isinstance(obj, set):
        for x in obj:
            rslt.add(transform(x))
    elif isinstance(obj, (int, long)):
        rslt = hex(obj)
    else:
        rslt = obj

    return rslt

element = transform(element)