Python 如果给定的键和值与字典列表中的匹配，则获取所有字典

如果键和值的给定值匹配，我想从dict列表中获取dict。下面是我的输入和预期输出

for i in json_data:
        logger.debug("I is :: {} ".format(type(i)))
        sql_operations = i['sqlOperations']
        for j in sql_operations:
            logger.debug("J is :: {} ".format(type(j)))
            for k,v in j.items():
                if k == 'operationType' and v == 'REPLACE View':
                     logger.debug("Key is {} and Item is {}".format(k,v))

输入：

[
    {
        "sqlFile": "test.sql",
        "noOfStatements": 3,
        "allQueries": "queries",
        "sqlOperations": [
            {
                "type": "CreateTable",
                "objectName": "objectname1",
                "schemaName": null
            },
            {
                "type": "CreateTable",
                "objectName": "objectname2",
                "schemaName": null
            },
            {
                "type": "DROP",
                "objectName": "objectname3",
                "schemaName": null
            }
        ]
    }
]

预期产出：

[
            {
                "type": "CreateTable",
                "objectName": "objectname1",
                "schemaName": null
            },
            {
                "type": "CreateTable",
                "objectName": "objectname2",
                "schemaName": null
            }
]

json_数据具有响应，sql_操作具有上述指定的输入。以下选项未按预期工作。我需要帮助确定问题以获得预期输出

for i in json_data:
        logger.debug("I is :: {} ".format(type(i)))
        sql_operations = i['sqlOperations']
        for j in sql_operations:
            logger.debug("J is :: {} ".format(type(j)))
            for k,v in j.items():
                if k == 'operationType' and v == 'REPLACE View':
                     logger.debug("Key is {} and Item is {}".format(k,v))

假设您使用json.load以python dict列表的形式获取输入，那么您可以使用列表理解来实现这一点吗

for i in json_data:
    ops = i.get('sqlOperations', [])
    select_dicts = [d for d in ops if d.get('type') == 'CreateTable']
    new_list.extend(select_dicts)

new_list
[{'type': 'CreateTable', 'objectName': 'objectname1', 'schemaName': None}, 
{'type': 'CreateTable', 'objectName': 'objectname2', 'schemaName': None}]

---

作为一个单一的列表，你可以做什么

output = [d for i in json_data for d in i['sqlOperations'] if d['type'] == 'CreateTable']

或者使用循环的标准

output = []
for i in json_data:
    for d in i['sqlOperations']:
        if d['type'] == 'CreateTable':
            output.append(d)

输出

[
  {
    "type": "CreateTable",
    "objectName": "objectname1",
    "schemaName": null
  },
  {
    "type": "CreateTable",
    "objectName": "objectname2",
    "schemaName": null
  }
]

---

注意：null在Python中不是有效的关键字。假设这是一个dict，尽管为null，这意味着json数据

我已经自由地将null更改为None，因为null将抛出一个NameError。这里的列表理解还生成列表列表，因此要获得输出，只选择第一个元素，但如果输入列表中有多个元素，它将起作用

json_data = [
    {
        "sqlFile": "test.sql",
        "noOfStatements": 3,
        "allQueries": "queries",
        "sqlOperations": [
            {
                "type": "CreateTable",
                "objectName": "objectname1",
                "schemaName": None
            },
            {
                "type": "CreateTable",
                "objectName": "objectname2",
                "schemaName": None
            },
            {
                "type": "DROP",
                "objectName": "objectname3",
                "schemaName": None
            }
        ]
    }
]

selected_data = [[v for v in jd['sqlOperations'] if v.get('type') == 'CreateTable'] for jd in json_data if jd.get('sqlOperations')]
print(selected_data[0])

结果

[{'type': 'CreateTable', 'objectName': 'objectname1', 'schemaName': None}, {'type': 'CreateTable', 'objectName': 'objectname2', 'schemaName': None}]

---

你能发布错误/输出你的gettingWhat是null应该在你的输入中，None，或者null吗？

[{'type': 'CreateTable', 'objectName': 'objectname1', 'schemaName': None}, {'type': 'CreateTable', 'objectName': 'objectname2', 'schemaName': None}]