Replacing function attribute with variable containing string

Question

I want to write code in a singe line to replace the following if-else code. Can I somehow use the status variable in the filter function directly as an attribute ?

status = request_queries.get('status', None)
if status == 'saved':
    queryset = queryset.filter(saved = True)
elif status == 'shortlisted':
    queryset = queryset.filter(shortlisted = True)
elif status == 'accepted':
    queryset = queryset.filter(accepted = True) 
elif status == 'rejected':
    queryset = queryset.filter(rejected = True)

willeM_ Van Onsem · Accepted Answer · 2019-08-10 18:09:58Z

1

If you can assume status will have as name a valid column name (that is a boolean field), you can use dictionary unpacking here:

status = request_queries.get('status', None)
queryset = queryset.filter(**{ status: True })

You might however want to check if it passes a valid column name, like:

status = request_queries.get('status', None)
if status in {'saved', 'shortlisted', 'accepted', 'rejected'}:
    queryset = queryset.filter(**{ status: True })

answered Aug 10, 2019 at 18:09

willeM_ Van Onsem

482k33 gold badges483 silver badges624 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

user11879807 Over a year ago

Getting the following error: "filter() keywords must be strings"

willeM_ Van Onsem Over a year ago

@user11879807: that's because if status is missing in the request_queries.get('status', None), it will return None, and hence error. This is one of the reasons why you should guard this with a membership check.

Thierry Lathuille · Accepted Answer · 2019-08-10 18:11:06Z

1

You can build a dict with the arguments and use it with **:

status = request_queries.get('status', None)
kwargs = {status: True}
queryset = queryset.filter(**kwargs)

answered Aug 10, 2019 at 18:11

Thierry Lathuille

24.4k10 gold badges49 silver badges57 bronze badges

Collectives™ on Stack Overflow

Replacing function attribute with variable containing string

2 Answers 2

2 Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related