Using a method in a same class (Python)

Question

class UnigramDist:
 def __init__(self, corpus):
 self.counts = defaultdict(float)
 self.total = 0.0
 self.train(corpus)
 # Get number of unique words (type)
 def getType(self, corpus):
 unique = []
 for sen in corpus:
 for word in sen:
 if(word not in unique):
 unique.append(word)
 return len(unique)
 def probWithLapalce(self, word):
 V = self.getType(corpus)
 word = word.strip()
 probVal = (self.counts[word] + 1) / (self.total + V)
 return math.log(probVal)
 #enddef

I am creating a class called UnigramDist that contains some methods that compute the probability of a unigram model, and I am trying to use the getType method in my probWithLaplace method in the same class.

But when I use this class in my test, it gives me a message that says:

 V = self.getType(corpus)
NameError: name 'corpus' is not defined

I don't get it since all other functions are using corpus just fine.

• juanpa.arrivillaga: Why would you imagine corpus is defined where you are calling getType, i.e. in probWithLapalce. I don't see it defined anywhere.

Answer 1

In the other methods, corpus is passed as a method parameter

def getType(self, corpus):
# ^^^^^^--- method parameter

and is therefore defined as a local variable. In your probWithLaplace method, however, corpus is neither passed as an argument, defined locally (inside the method body) nor globally (at module level) before you use it:

# no global (module level) variable corpus ...
def probWithLaplace(self, word): # ... and no corpus here ...
 # ... or here
 V = self.getType(corpus) # hence, corpus is not defined here

Answer 2

Your other functions are getting corpus as a parameter, so it's a local variable in those functions.

You could set self.corpus = corpus in your __init__ function, which would then make self.corpus available to all of that class's functions. (as long as they know about self - that is, as long as they're instance methods)