有时候使用es查询出的结果包含多个字段，如果数据中仅仅包含几个字段时，我们是很容易挑出自己需要的字段值，但是如果数据中包含几十或者几百甚至更多时，尤其是数据中嵌套好多层时，不容易直接挑取出需要的值，这时候可以借助程序直接查找出来。或者针对性的直接查询时就限定条件查询某些字段的值。

直接从es中查询出的示例数据：

{
	"took": 918,
	"timed_out": false,
	"_shards": {
		"total": 1,
		"successful": 1,
		"skipped": 0,
		"failed": 0
	},
	"hits": {
		"total": {
			"value": 4,
			"relation": "eq"
		},
		"max_score": 1.0,
		"hits": [{
				"_index": "test",
				"_type": "user",
				"_id": "QHi1UoIBpyNh4YQ4T1Sq",
				"_score": 1.0,
				"_source": {
					"id": 1001,
					"name": "张三",
					"age": 20,
					"sex": "男",
					"grade": {
						"Chinese": 99,
						"Math": 98,
						"English": 96
					}
				}
			},
			{
				"_index": "test",
				"_type": "user",
				"_id": "1002",
				"_score": 1.0,
				"_source": {
					"id": 1002,
					"name": "李四",
					"age": 23,
					"sex": "女",
					"grade": {
						"Chinese": 98,
						"Math": 99,
						"English": 97
					}
				}
			},
			{
				"_index": "test",
				"_type": "user",
				"_id": "1003",
				"_score": 1.0,
				"_source": {
					"id": 1003,
					"name": "王五",
					"age": 27,
					"sex": "男",
					"grade": {
						"Chinese": 93,
						"Math": 90,
						"English": 99
					}
				}
			},
			{
				"_index": "test",
				"_type": "user",
				"_id": "1004",
				"_score": 1.0,
				"_source": {
					"id": 1004,
					"name": "赵六",
					"age": 29,
					"sex": "女",
					"grade": {
						"Chinese": 100,
						"Math": 95,
						"English": 94
					}
				}
			}
		]
	}
}

使用python打印出需要的字段值：

import json
import jmespath


with open('text.txt', 'r', encoding='utf-8') as f:
    data = f.read()

json_data = json.loads(data)
# print(json_data)
sources = json_data.get('hits').get('hits')
# print(sources)
for source in sources:
    # print(source)
    data = source.get('_source')
    print(data)
    valid_fields = '{name: name, Chinese_grade: grade.Chinese}'
    ret = jmespath.search(valid_fields, data)
    print(ret)

运行结果：

注意：使用json.load()时，会把文本中的fase、true直接变为False、True

参考博文：

python中jmespath库用法详解_IT之一小佬的博客-CSDN博客_jmespath python