以下是一个遍历字典列表并保存重复数据的示例代码：

data = [
    {"name": "John", "age": 25},
    {"name": "Alice", "age": 30},
    {"name": "John", "age": 35},
    {"name": "Bob", "age": 25},
    {"name": "Alice", "age": 40}
]

# 创建一个空字典来保存重复数据
duplicates = {}

# 遍历字典列表
for item in data:
    name = item["name"]
    age = item["age"]
    
    # 检查是否有重复的姓名
    if name in duplicates:
        duplicates[name].append(age)
    else:
        duplicates[name] = [age]

# 打印结果
for name, ages in duplicates.items():
    if len(ages) > 1:
        print(f"{name}的年龄重复：{ages}")

运行以上代码将输出以下结果：

John的年龄重复：[25, 35]
Alice的年龄重复：[30, 40]