python - negative integers in django -

i'm trying make query in postgresql database. need multiply -1 id before query.

def getrelation(request,id):     #id = id * -1     #osmobject = get_object_or_404(planetosmpolygon,osm_id=int(id))     return httpresponse(id)     #return httpresponse(osmobject.way.geojson) 

this view. code works, however, if uncomment multiply, there nothing in browser. can't see negative id. mistake?

if uncomment get_object_404, have :

invalid literal int() base 10: ''

that's why tried int().

this problem seems simple , don't understand why. begin in django.

thanks

parameters captured urls (your id here) injected strings

you need coerce before start working it

something like

def getrelation(request, id):     id = int(id)     # rest of view 

update (re: blank string)

python lets repeat strings overloading multiplication operator

>>> "foo" * 3 'foofoofoo' 

when try multiply string (containing id, string) -1, "-1 copies", returns empty string

>>> "foo" * -1 '' 

or in case:

>>> "12" * -1 '' >>> int("12") * -1 -12