如何从有条件的字典列表中提取字典

Question

How to extract from the json with condition

I have a list of dictionary. I need extract some of the dictionary with some conditions

• If for cross field I need "AND" condition

• for same field array I need to OR condition

1. I need to search subject which is Physics or Accounting this is array of fields(OR) statement

   AND

2. I need to search type is Permanent or GUEST condition this is array of fields(OR) statement

   AND

3. I need to search Location is NY (&) condition

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'}]

Expected out is 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

The following simple approach with a nested if clause solves the issue. The and condition is done via the nested if and the or conditions is simply done via or .

The in operator works for string values and list values, therefore it can be used interchangeably and results in the expected out. BUT this approach expects that there are no specific subjects like 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)

Answer 2

The problem here is mostly that your data is not uniform, sometimes it's strings, sometimes it's list. Let's try:

# 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)]

Output:

[{'id': 2,
  'name': 'AB',
  'subject': ['Physics', 'Engineering'],
  'type': 'Permanent',
  'Location': 'NY'},
 {'id': 4,
  'name': 'ABCD',
  'subject': ['Physics', 'Engineering'],
  'type': ['Contract', 'Guest'],
  'Location': 'NY'}]