python - 在上下文中评估变量

Question

假设我有一个 django 上下文 C 并且我想在 C 中计算变量 var (不处理模板)，该怎么办？

class PersonClass: pass
p = PersonClass
p.name = 'Test'

C = Context({"person": p})
# let's say I want to evaluate person.name

evaluate(C, 'person.name') should give 'Test' # like {{person.name}} in template would give Test

Answer 1

这行得通吗:

>>> C = Context({"person": p})
>>> C.get("person")
<class '__main__.PersonClass'>
>>> C.get("person").name
'Test'

编辑:更通用的版本:

def get_attr_from_context(ctx, attr_str):
    attrs = iter(attr_str.split('.'))
    ans = ctx.get(next(attrs))
    for attr in attrs:
        ans = getattr(ans, attr)
    return ans

# Prints 'Test'
print(get_attr_from_context(C, 'person.name'))