What does this interface syntax mean in python?
interface, python, syntax
Solution
- The type function with 3 arguments creates a class. So that would be equivalent to this code:
`class dummy(object): pass `
- In Python you can add an attribute to an object at any time. If it doesn't exist already, it will get created, essentially inserted into a dict that represents the object's attributes.
Problem
I am doing cs224n's assignment.In function `test_word2vec`, there is some python syntax I don not understand: ``` """ Interface to the dataset for negative sampling """ dataset = type('dummy', (), {})() def dummySampleTokenIdx(): return random.randint(0, 4) def getRandomContext(C): tokens = ["a", "b", "c", "d", "e"] return tokens[random.randint(0,4)], \ [tokens[random.randint(0,4)] for i in xrange(2*C)] dataset.sampleTokenIdx = dummySampleTokenIdx dataset.getRandomContext = getRandomContext ``` Question one: What does `dataset = type('dummy', (), {})()` mean ? Question two: In `dataset.sampleTokenIdx = dummySampleTokenIdx` , I do not think `dataset` has attribute `sampleTokenIdx` . So, why can dataset invoke it ?