Python_json数据检索与定位之jsonPath类库

json数据检索与定位之jsonPath类库

 

by:授客 QQ：1033553122

实践环境

win7 64

Python 3.4.0

jsonpath_ng-1.4.3-py2.py3-none-any.whl

下载地址：

https://pypi.org/project/jsonpath-ng/#files

https://pan.baidu.com/s/1AdbGqz1brNYBOqmIbWaAYg

使用详解

官方实例

>>> from jsonpath_ng import jsonpath, parse

>>> jsonpath_expr = parse('foo[*].baz')

# 提取值

>>> [match.value for match in jsonpath_expr.find({'foo':[{'baz':1}, {'baz':2}]})]

[1, 2]

# 获取匹配值对应的路径

>>> [str(match.full_path) for match in jsonpath_expr.find({'foo': [{'baz': 1}, {'baz': 2}]})]

['foo.[0].baz', 'foo.[1].baz']

# 自动提供id

>>> [match.value for match in parse('foo[*].id').find({'foo': [{'id': 'bizzle'}, {'baz': 3}]})]

['bizzle']

>>> jsonpath.auto_id_field = 'id'

>>> [match.value for match in parse('foo[*].id').find({'foo': [{'id': 'bizzle'}, {'baz': 3}]})]

['foo.bizzle', 'foo.[1]']

# 扩展功能之一 命名操作符 `parent`

>>> [match.value for match in parse('a.*.b.`parent`.c').find({'a': {'x': {'b': 1, 'c': 'number one'}, 'y': {'b': 2, 'c': 'number two'}}})]

['number one', 'number two']

>>> ['number two', 'number one']

使用扩展的解析器

好处是有更强大的扩展功能

>>> from jsonpath_ng.ext import parse

>>> jsonpath_expr = parse('foo[*].baz')

jsonpath 语法

基础语法(Atomic expressions)

$            根对象

`this`      当前对象

`foo`       More generally, this syntax allows "named operators" to extend JSONPath is arbitrary ways

field       指定具体的字段

[ field ]   同field

[ idx ]     数组访问 Array access, described below (this is always unambiguous with field access)

例子

获取根对象

>>> parse('$').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}]})

[DatumInContext(value={'key2': {'id': 2}, 'key3': [{'id': 3}, {'name': 'shouke'}], 'key1': {'id': 1}}, path=Root(), context=None)]

>>> [match.value for match in parse('$').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}]})]

[{'key2': {'id': 2}, 'key3': [{'id': 3}, {'name': 'shouke'}], 'key1': {'id': 1}}]

获取一级键对应的值

>>> [match.value for match in parse('key1').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}]})]

[{'id': 1}]

>>> [match.value for match in parse('[key1]').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}]})]

[{'id': 1}]

# 注意：单独使用 filed、 [filed] 语法，field仅支持字典的一级键

[{'key2': {'id': 2}, 'key3': [{'id': 3}, {'name': 'shouke'}], 'key1': {'id': 1}}]

>>> [match.value for match in parse('id').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}]})]

[]

# 注意：单独使用 filed、 [filed] 语法，根对象必须是字典，不能是数组

>>> [match.value for match in parse('[key1]').find([{'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}]}])]

[]

数组访问

>>> [match.value for match in parse('[0]').find([{'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}]}])]

[{'key2': {'id': 2}, 'key3': [{'id': 3}, {'name': 'shouke'}], 'key1': {'id': 1}}]

jsonpath操作符

jsonpath1 . jsonpath2     匹配jsonpath2，并且父节点匹配jsonpath1的所有节点(All nodes matched by jsonpath2 starting at any node matching jsonpath1) 注意：仅针对字典可用

注：有无空格不影响，比如jsonpath1.jsonpath2 下同

jsonpath [ whatever ]     如果是字典，同jsonpath.whatever，如果是数组，则表示按索引访问数组

jsonpath1 .. jsonpath2    匹配jsonpath2，并且由匹配jsonpath1的父节点派生的所有节点

jsonpath1 where jsonpath2     匹配jsonpath1并且携带一个匹配jsonpath2直接子节点(非派生子节点)的所有节点（Any nodes matching jsonpath1 with a child matching jsonpath2）

jsonpath1 | jsonpath2       匹配jsonpath1，或者jsonpath2的所有节点的集合（注：有时候结果似乎和描述不符，具体见例子

例子

jsonpath1 . jsonpath2

>>> [match.value for match in parse('key1.id').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}]})]

[1]

jsonpath [ whatever ]

>>> [match.value for match in parse('key1[id]').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}]})]

[1]

>>> [match.value for match in parse('key3[0]').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}]})]

[{'id': 3}]

jsonpath1 .. jsonpath2

>>> [match.value for match in parse('key3..id').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':{'key4':{'key5':{'id':3, 'name':'shouke'}}}})]

[3]

>>> [match.value for match in parse('key3..id').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}, {'id':4, 'name':'keshou'}]})]

[3, 4]

jsonpath1 where jsonpath2

>>> [match.value for match in parse('key2 where id').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}, {'id':4, 'name':'keshou'

[{'id': 2}]

注意：匹配jsonpath2的必须是直接子节点

>>> [match.value for match in parse('key3 where id').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}, {'id':4, 'name':'keshou'

[]

>>> [match.value for match in parse('key3 where id').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':{'key4':{'key5':{'id':3, 'name':'shouke'}}}})]

[]

jsonpath1 | jsonpath2

>>> [match.value for match in parse('key1 | key3 ').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':{'key4':{'key5':{'id':3, 'name':'shouke'}}}})]

[{'id': 1}, {'key4': {'key5': {'name': 'shouke', 'id': 3}}}]

>>> [match.value for match in parse('key1 | key3.key4 ').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':{'key4':{'key5':{'id':3, 'name':'shouke'}}}})]

[{'key5': {'name': 'shouke', 'id': 3}}]

字段说明(field)

fieldname   来自当前对象的字段名称

"fieldname" 同上，允许fieldname中包含指定字符

'fieldname' 同上

*            任意字段名称

field , field   指定多个字段

例子

*

>>> [match.value for match in parse('key1.*').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':{'key4':{'key5':{'id':3, 'name':'shouke'}}}})]

[1]

注意：如果是jsonpath1.* 返回的是最后层级的值

>>> [match.value for match in parse('key3.*').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':{'key4':{'key5':{'id':3, 'name':'shouke'}}}})]

[{'key5': {'name': 'shouke', 'id': 3}}]

>>> [match.value for match in parse('key3.*').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}, {'id':4, 'name':'keshou'}]})]

[]

>>> [match.value for match in parse('key1, key2, key3').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}, {'id':4, 'name':'kesh

[{'id': 1}, {'id': 2}, [{'id': 3}, {'name': 'shouke'}, {'name': 'keshou', 'id': 4}]]

>>> [match.value for match in parse('*.*[*]').find({'root':{'key':[{'id':'tizza'}, {'name':'hizza'}]}})]

[{'id': 'tizza'}, {'name': 'hizza'}]

field , field   指定多个字段

>>> [match.value for match in parse('key1, key2, key3').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}, {'id':4, 'name':'keshou'}]

[{'id': 1}, {'id': 2}, [{'id': 3}, {'name': 'shouke'}, {'name': 'keshou', 'id': 4}]]

数组索引说明（idx）

[n] 数组索引

[start?:end?]   含义同python的数组切片，注意：数组索引不包含end,可以不指定start, end，或者两者之一

[*] 任意索引，表示返回整个数组元素，等同于[:]

例子

[*]

[match.value for match in parse('key3[*]').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}, {'id':4, 'name':'keshou'}]})]

[{'id': 3}, {'name': 'shouke'}, {'name': 'keshou', 'id': 4}]

[start?:end?]

>>> [match.value for match in parse('key3[0:1]').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}, {'id':4, 'name':'keshou'}]})]

[{'id': 3}]

>>> [match.value for match in parse('key3[0:]').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}, {'id':4, 'name':'keshou'}]})]

[{'id': 3}, {'name': 'shouke'}, {'name': 'keshou', 'id': 4}]

>>> [match.value for match in parse('key3[:1]').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}, {'id':4, 'name':'keshou'}]})]

[{'id': 3}]

>>> [match.value for match in parse('key3[:]').find({'key1':{'id': 1}, 'key2':{'id': 2}, 'key3':[{'id':3}, {'name':'shouke'}, {'id':4, 'name':'keshou'}]})]

[{'id': 3}, {'name': 'shouke'}, {'name': 'keshou', 'id': 4}]

>>>

更多功能参考官方文档

参考链接

https://pypi.org/project/jsonpath-ng/#files