Python and Schools

[Greg Brondo]

Aahz wrote:
> In article <v9e21mhemm8c2 at corp.supernews.com>,
> Paul Watson <pwatson at redlinec.com> wrote:
> 
>>We need to teach students correct design priciples to build something
>>greater than what already exists.  We will never get very far if we
>>require everyone to start with a quark or atom.  Yes, of course we need
>>some people who design silicon and create microcode.  They will learn
>>the low-level details what they need to know as they need it.  Knowing
>>great design and organization principles will enable them to make the
>>most of it.
> 
> 
> While there's some truth to that, try explaining why the following code
> is a Bad Idea to someone who has no basic understanding of CS:
> 
>     s = ''
>     for i in range(1000000):
>         s += str(i)
> 
> Knowing the difference between O(N) and O(N^2) is critical to writing
> even the simplest programs.  OTOH, I do agree with you that focusing on
> programming as a craft is more important to being a programmer than
> learning CS.

I understand why the code is bad (copying the string each time in
memory as it grows).  However, I've never understood the notation's
O(N) and O(N2)?

Thanks,
Greg Brondo