"students" entries
Are there some students who can’t learn how to code?
Change tactics or give up: It's a crossroads many teachers face when students don't understand the code.
I can never forget an evening late into a semester of my Introduction to Python course, during which I asked my students a question about user-defined classes. Here’s the code I had put on the board:
class MyClass(object):
var = 0
def __init__(self): # called
MyClass.var = MyClass.var + 1
x = MyClass() # new instance created
y = MyClass() # new instance created
As new information for this particular lesson, I informed them that every time a new MyClass
instance is created, the __init__()
method is called implicitly. In other words, the code above calls __init__()
twice, and in executing the code in __init__()
, the variable MyClass.var
is being incremented — so this is also happening twice.
So, I asked them: after the above code is executed, what is the value of MyClass.var
?
The hand of this class’ most enthusiastic student shot into the air.
“One!” He answered proudly. And for a moment my mouth stood open. Read more…