Question

I am creating class instances by running a text file and slicing the words into a list, I am using white space as the split point.

I am then creating objects of the class Word based on the names in the array using this bit of code.

exec("%s = Word(title)" % (title))

I know the objects are being created as I have the object print upon initialization.

My problem is that if I try to access these objects I get:

blue.getWordName()    
NameError: global name 'blue' is not defined

I am really confused and have tried searching for answers but I’m not sure I am using the correct terminology.

I have figured out that I can use a dictionary to achieve my aim but I really want to understand class instances more.

Is there a law against creating classes on the fly from list items?

I did try to include all of the code but it wouldn’t let me so I’ll include what I think is most relevant:

class Word():
def __init__(self, name):
    print 'You have just created me and I\'m called ' + name
    self.name = name


if count > 0 and wordArray[count - 1] == 'is':
        title = wordArray[count]
        if title not in checkKeyWords():
            exec("%s = Word(title)" % (title)) #set class from list item.


            if word in verbArray:
                exec("%s.setWordType('verb')" % (title))

Eventually I call the below function which has been created and is spelled correctly, I have also made sure that ‘blue’ is definitely in the list.

blue.getWordName() 

Answer 1

Let me start by saying that I totally agree with the other answer, use dictionaries instead. If you want an answer to your problem, please make your example reproducible. A slightly adapted version of your code:

class Word():
  def __init__(self, name):
    print 'You have just created me and I\'m called ' + name
    self.name = name
    self.wordType = None
  def setWordType(self, type_string):
    print "Hey, and the method works!"
    self.wordType = type_string

wordArray = ["spam","ni", "is","blue"]
count = 3
if count > 0 and wordArray[count - 1] == 'is':
  title = wordArray[count]
  exec("%s = Word(title)" % (title)) #set class from list item.
  exec("%s.setWordType('verb')" % (title))

Works fine:

> python bla.py 
You have just created me and I'm called blue
Hey, and the method works!

It might be that you have your indentation messed up. You check that the title is no in a list of keywords (if title not in checkKeyWords()), and create the object only if that holds. Could be that you refer to the blue object somewhere in the code, while it was not created. But without a solid example, this is impossible to tell.