On Thursday 19 August 2010, it occurred to Baba to exclaim:
> def countSubStringMatchRecursive(target,key):
> counter=0
> fsi=0 #fsi=find string index
> if len(key)==len(target): #base case
> if key==target:
> counter+=1
> elif len(key)<len(target):
> while fsi<len(target):
> fsi=target.find(key,fsi)
> if fsi!=-1:
> counter+=1
> else:
> break
> fsi=fsi+1
> else:
> print 'key is longer than target...'
>
> print '%s is %d times in the target string' %(key,counter)
>
> countSubStringMatchRecursive("atgacatgcacaagtatgcat","atgacatgcacaagtatgcat
> atgc")
This is not recursive. In fact, it's exactly the same approach as
the first one, plus a bit of an if statement.
Take another good look at the definition of "recursion" I'm sure you were
given.
To sum it up:
"iterate": use a loop. and again. and again. and again. and again. and aga....
"recurse": consider. recurse.
This is another good one:
http://mytechquest.com/blog/wp-content/uploads/2010/05/From-a-Programming-Book.jpg
- Thomas
PS: If you think you're thinking, then you're really only thinking that
you're thinking. Or are you?
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