python检查列表中键的字典值是否重复

Question

我有一组数据，我想检查我的data中的value是否重复。
我的方法在下面，我觉得有点复杂，所以我想问一下有没有更好的方法呢？

data =[
        {"name": "ali", 
         "value": "ABC" 
         },
        {"name": "bob", 
         "value": "ABC" 
         },
        {"name": "cathy", 
         "value": "ABC" 
         },
        {"name": "david", 
         "value": "ABCD" 
         },
    ]


check_list = []
duplicate_value = []
for d in data:
    if d["value"] not in check_list:
        check_list.append(d["value"]) 
    else:
        if d["value"] not in duplicate_value:
            duplicate_value.append(d["value"])


print  "You have duplicate value:", duplicate_value 

Answer 1

from collections import Counter

data =[
        {"name": "ali", 
         "value": "ABC" 
         },
        {"name": "bob", 
         "value": "ABC" 
         },
        {"name": "cathy", 
         "value": "ABC" 
         },
        {"name": "david", 
         "value": "ABCD" 
         },
    ]

arr = [d['value'] for d in data]

duplicate_values = [k for k, v in Counter(arr).items() if v > 1]

print('Duplicate values - ', duplicate_values)

输出-

Duplicate values -  ['ABC']