My eval syntax isn't right. Namely, for each category, I'd like to output a ModelChoiceField named category_task, ie. if category were 'fun', then a radio select field 'fun_tasks' would be output.
categories = Category.objects.all()
for category in categories:
eval(category)_tasks = form.ModelChoiceField(
queryset = Task.objects.filter(method__category=category),
widget = RadioSelect
)
“eval is evil.”
OK, it has its uses, but 90% of eval usage (in any language) is misconceived, so if you find yourself writing an eval you should stop and examine what you're doing with extreme suspicion.
eval(category)_tasks = x
If you are doing an assignment, that's a statement rather than an expression, so you'd have to use exec rather than eval:
exec category+'_tasks= x'
However exec is just as evil as eval!
You can write a variable in Python without having to parse/evaluate Python code:
locals()[category+'_tasks']= x
or, if you want to write a global variable instead of one in the current scope, replace locals() with globals().
Although this is better than eval/exec, it is still rather code-smelly. You rarely actually want completely dynamically-named variables; a lookup is usually much cleaner:
catlookup= {}
catlookup[category]= x
although without more context it's difficult to say what's best for your case.
