Why is Python class not recognizing static variable

Question

I am trying to make a class in Python with static variables and methods (attributes and behaviors)

import numpy

class SimpleString():    
    popSize = 100         


        

Answer 1

You need to use self or the class object to access class attributes:

def __init__(self):
    pop = numpy.empty(self.popSize, object)
    target = getTarget()
    targetSize = len(target)

or

def __init__(self):
    pop = numpy.empty(SimpleString.popSize, object)
    target = getTarget()
    targetSize = len(target)

The latter form is really only needed if you want to bypass an instance attribute with the same name:

>>> class Foo(object):
...     bar = 42
...     baz = 42
...     def __init__(self):
...         self.bar = 38
...     def printBar(self):
...         print self.bar, Foo.bar
...     def printBaz(self):
...         print self.baz, Foo.baz
... 
>>> f = Foo()
>>> f.printBar()
38 42
>>> f.printBaz()
42 42

Here self.bar is an instance attribute (setting always happens on the object directly). But because there is no baz instance attribute, self.baz finds the class attribute instead.