如何筛选嵌套JSON数组中likes值大于50的数据行？

嘿，这个问题我太熟悉了！要筛选嵌套JSON数组里likes字段值大于50的数据，得看你用什么工具来处理——我给你分享两个最常用的场景，都是日常处理JSON的利器：

用Python处理 #

Python的json模块可以轻松搞定这个需求，不管你是单条数据还是多条数据组成的数组，都能灵活处理。

单条数据的情况 #

比如你给出的示例JSON，我们可以解析后筛选locations中符合条件的元素，同时保留外层的id和name：

import json

# 你的示例JSON数据（这里我多加了一个likes=40的条目方便对比）
json_data = '''
{ 
  "id":2, 
  "name":"TEST", 
  "locations":[ 
    { "cityName":"NEW YORK", "lat":123, "lon":456, "likes":1000, "dislikes":5 },
    { "cityName":"LONDON", "lat":789, "lon":101, "likes":40, "dislikes":20 }
  ] 
}
'''

# 把JSON字符串转成Python字典
data = json.loads(json_data)

# 筛选locations中likes>50的条目，重新组织成新的JSON结构
filtered_result = {
    "id": data["id"],
    "name": data["name"],
    "locations": [loc for loc in data["locations"] if loc["likes"] > 50]
}

# 格式化输出结果
print(json.dumps(filtered_result, indent=2))

运行后会输出：

{
  "id": 2,
  "name": "TEST",
  "locations": [
    {
      "cityName": "NEW YORK",
      "lat": 123,
      "lon": 456,
      "likes": 1000,
      "dislikes": 5
    }
  ]
}

多条数据行的情况 #

如果你的原始数据是多个数据行组成的数组（比如批量数据），可以在外层再套一层列表推导，还能可选过滤掉筛选后locations为空的行：

import json

# 多条数据的示例数组
json_array_data = '''
[
  { 
    "id":2, 
    "name":"TEST", 
    "locations":[ 
      { "cityName":"NEW YORK", "likes":1000 },
      { "cityName":"LONDON", "likes":40 }
    ] 
  },
  { 
    "id":3, 
    "name":"ANOTHER TEST", 
    "locations":[ 
      { "cityName":"PARIS", "likes":60 },
      { "cityName":"TOKYO", "likes":30 }
    ] 
  },
  { 
    "id":4, 
    "name":"EMPTY TEST", 
    "locations":[ 
      { "cityName":"SYDNEY", "likes":30 }
    ] 
  }
]
'''

data_array = json.loads(json_array_data)
filtered_rows = [
    {
        "id": row["id"],
        "name": row["name"],
        "locations": [loc for loc in row["locations"] if loc["likes"] > 50]
    }
    for row in data_array
    # 可选：去掉筛选后locations为空的行
    if any(loc["likes"] > 50 for loc in row["locations"])
]

print(json.dumps(filtered_rows, indent=2))

这段代码会自动排除id=4的那条数据，因为它的locations里没有符合条件的元素。

用jq命令行工具处理 #

如果你习惯用命令行处理JSON，jq绝对是首选工具，语法简洁高效。

单条数据的情况 #

直接用map(select(...))筛选locations数组，并用|=把结果赋值回原字段：

echo '{"id":2,"name":"TEST","locations":[{"cityName":"NEW YORK","lat":123,"lon":456,"likes":1000,"dislikes":5},{"cityName":"LONDON","lat":789,"lon":101,"likes":40,"dislikes":20}]}' | jq '.locations |= map(select(.likes > 50))'

多条数据行的情况 #

外层用map()遍历每个数据行，同样可以加select(.locations != [])去掉空的行：

echo '[ {"id":2,"name":"TEST","locations":[{"cityName":"NEW YORK","likes":1000},{"cityName":"LONDON","likes":40}]}, {"id":3,"name":"ANOTHER TEST","locations":[{"cityName":"PARIS","likes":60},{"cityName":"TOKYO","likes":30}]}, {"id":4,"name":"EMPTY TEST","locations":[{"cityName":"SYDNEY","likes":30}]} ]' | jq 'map( .locations |= map(select(.likes >50)) | select(.locations != []) )'

内容的提问来源于stack exchange，提问作者Probine Business