"learn to code" 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:
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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…