如何从有条件的字典列表中提取字典

Question

如何从带有条件的json中提取我有一个字典列表。我需要在某些条件下提取一些字典如果对于跨字段我需要“AND”条件对于相同的字段数组，我需要 OR 条件我需要搜索subject哪个是Physics或Accounting这是字段数组（OR）语句和我需要搜索type是Permanent或GUEST条件这是字段数组（OR）语句和我需要搜索Locationis NY(&) 条件test = [{'id':1,'name': 'A','subject': ['Maths','Accounting'],'type':'Contract', 'Location':'NY'},      { 'id':2,'name': 'AB','subject': ['Physics','Engineering'],'type':'Permanent','Location':'NY'},    {'id':3,'name': 'ABC','subject': ['Maths','Engineering'],'type':'Permanent','Location':'NY'},{'id':4,'name':'ABCD','subject': ['Physics','Engineering'],'type':['Contract','Guest'],'Location':'NY'}]预期输出是 id[{ 'id':2,'name': 'AB','subject': ['Physics','Engineering'],'type':'Permanent','Location':'NY'},{'id':4,'name':'ABCD','subject': ['Physics','Engineering'],'type':['Contract','Guest'],'Location':'NY'}]

Answer 1

这里的问题主要是你的数据不统一，有时是字符串，有时是列表。咱们试试吧：

# turns the values into set for easy comparison

def get_set(d,field):

    return {d[field]} if isinstance(d[field], str) else set(d[field])

    

# we use this to filter

def validate(d):

    # the three lines below corresponds to the three conditions listed

    return get_set(d,'subject').intersection({'Physics','Accounting'}) and \

           get_set(d,'type').intersection({'Permanent', 'Guest'}) and \

           get_set(d,'Location')=={'NY'}

result = [d for d in test if validate(d)]

输出：

[{'id': 2,

  'name': 'AB',

  'subject': ['Physics', 'Engineering'],

  'type': 'Permanent',

  'Location': 'NY'},

 {'id': 4,

  'name': 'ABCD',

  'subject': ['Physics', 'Engineering'],

  'type': ['Contract', 'Guest'],

  'Location': 'NY'}]

Answer 2

以下带有嵌套 if 子句的简单方法解决了该问题。条件and是通过嵌套完成的if，or条件只是通过 完成or。

该in运算符适用于字符串值和列表值，因此它可以互换使用并产生预期的结果。但这种方法期望没有像XYZ Accounting.

result = []

for elem in test:

    

    # Check Location

    if elem['Location'] == 'NY':

    

        # Check subject

        subject = elem['subject']

        if ('Accounting' in subject) or ('Physics' in subject):

        

            # Check type

            elem_type = elem['type']

            if ('Permanent' in elem_type) or ('Guest' in elem_type):

                # Add element to result, because all conditions are true

                result.append(elem)