Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
197 views
in Technique[技术] by (71.8m points)

python - Creating class instance properties from a dictionary?

I'm importing from a CSV and getting data roughly in the format

{ 'Field1' : 3000, 'Field2' : 6000, 'RandomField' : 5000 }

The names of the fields are dynamic. (Well, they're dynamic in that there might be more than Field1 and Field2, but I know Field1 and Field2 are always going to be there.

I'd like to be able to pass in this dictionary into my class allMyFields so that I can access the above data as properties.

class allMyFields:
    # I think I need to include these to allow hinting in Komodo. I think.
    self.Field1 = None
    self.Field2 = None

    def __init__(self,dictionary):
        for k,v in dictionary.items():
            self.k = v
            #of course, this doesn't work. I've ended up doing this instead
            #self.data[k] = v
            #but it's not the way I want to access the data.

q = { 'Field1' : 3000, 'Field2' : 6000, 'RandomField' : 5000 }
instance = allMyFields(q)
# Ideally I could do this.
print q.Field1

Any suggestions? As far as why -- I'd like to be able to take advantage of code hinting, and importing the data into a dictionary called data as I've been doing doesn't afford me any of that.

(Since the variable names aren't resolved till runtime, I'm still going to have to throw a bone to Komodo - I think the self.Field1 = None should be enough.)

So - how do I do what I want? Or am I barking up a poorly designed, non-python tree?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

You can use setattr (be careful though: not every string is a valid attribute name!):

>>> class AllMyFields:
...     def __init__(self, dictionary):
...         for k, v in dictionary.items():
...             setattr(self, k, v)
... 
>>> o = AllMyFields({'a': 1, 'b': 2})
>>> o.a
1

Edit: let me explain the difference between the above code and SilentGhost's answer. The above code snippet creates a class of which instance attributes are based on a given dictionary. SilentGhost's code creates a class whose class attributes are based on a given dictionary.

Depending on your specific situation either of these solutions may be more suitable. Do you plain to create one or more class instances? If the answer is one, you may as well skip object creation entirely and only construct the type (and thus go with SilentGhost's answer).


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...