展平包含列表和元组列表的字典

nested_dict = {
    'a': [1, 2, 3],
    'b': [(4, 5), (6, 7)],
    'c': {'d': [8, 9]}
}

def flatten_dict(d, parent_key='', sep='_'):
    items = []
    for k, v in d.items():
        new_key = f"{parent_key}{sep}{k}" if parent_key else k
        if isinstance(v, dict):
            items.extend(flatten_dict(v, new_key, sep=sep).items())
        elif isinstance(v, list) or isinstance(v, tuple):
            for i, elem in enumerate(v):
                items.append((f"{new_key}{sep}{i}", elem))
        else:
            items.append((new_key, v))
    return dict(items)

flattened = flatten_dict(nested_dict)
print(flattened)

{
    'a_0': 1,
    'a_1': 2,
    'a_2': 3,
    'b_0_0': 4,
    'b_0_1': 5,
    'b_1_0': 6,
    'b_1_1': 7,
    'c_d_0': 8,
    'c_d_1': 9
}

def flatten_dict_safe(d, parent_key='', sep='_', seen=None):
    if seen is None:
        seen = set()
    items = []
    for k, v in d.items():
        new_key = f"{parent_key}{sep}{k}" if parent_key else k
        if new_key in seen:
            continue
        seen.add(new_key)
        if isinstance(v, dict):
            items.extend(flatten_dict_safe(v, new_key, sep=sep, seen=seen).items())
        elif isinstance(v, list) or isinstance(v, tuple):
            for i, elem in enumerate(v):
                items.append((f"{new_key}{sep}{i}", elem))
        else:
            items.append((new_key, v))
    return dict(items)