How do I use a string as a keyword argument?
Question:
Specifically, I’m trying to use a string to arbitrairly filter the ORM. I’ve tried exec and eval solutions, but I’m running into walls. The code below doesn’t work, but it’s the best way I know how to explain where I’m trying to go
from gblocks.models import Image
f = 'image__endswith="jpg"' # Would be scripted in another area, but passed as text <user input>
d = Image.objects.filter(f)
#for the non-django pythonistas:
d = Image.objects.filter(image__endswith="jpg")
# would be the non-dynamic equivalent.
Answers:
d = Image.objects.filter(**{'image__endswith': "jpg"})
The eval option should work fine, as long as you wrap it around the entire expression, not just the f:
f = 'image__endswith="jpg"'
d = eval('Image.objects.filter(' + f + ')')
You’d need to split out the value from the keyword, then set up a dict using the keyword as the key, and the value as the value. You could then use the double-asterisk function paramater with the dict.
So…
keyword, sep, value = f.partition('=')
kwargs = {keyword: value.strip('"')}
d = Image.objects.filter(**kwargs)
Note, this code assumes that there won’t be any equals signs ‘=’ in the keyword (they’ll only be used to separate the keyword from the value), and the value will be wrapped in quotes.
Specifically, I’m trying to use a string to arbitrairly filter the ORM. I’ve tried exec and eval solutions, but I’m running into walls. The code below doesn’t work, but it’s the best way I know how to explain where I’m trying to go
from gblocks.models import Image
f = 'image__endswith="jpg"' # Would be scripted in another area, but passed as text <user input>
d = Image.objects.filter(f)
#for the non-django pythonistas:
d = Image.objects.filter(image__endswith="jpg")
# would be the non-dynamic equivalent.
d = Image.objects.filter(**{'image__endswith': "jpg"})
The eval option should work fine, as long as you wrap it around the entire expression, not just the f:
f = 'image__endswith="jpg"'
d = eval('Image.objects.filter(' + f + ')')
You’d need to split out the value from the keyword, then set up a dict using the keyword as the key, and the value as the value. You could then use the double-asterisk function paramater with the dict.
So…
keyword, sep, value = f.partition('=')
kwargs = {keyword: value.strip('"')}
d = Image.objects.filter(**kwargs)
Note, this code assumes that there won’t be any equals signs ‘=’ in the keyword (they’ll only be used to separate the keyword from the value), and the value will be wrapped in quotes.