Recursion in Python

I worked through recursion in the Computational Statistics in Python tutorial, getting up to speed on Python, and although this code is similar to the tutorial, I did try to 'make it mine':

 # Recursion  
 """http://people.duke.edu/~ccc14/sta-663/FunctionsSolutions.html#recursion"""  
   
 # Correct Example  
 def fibonacci(n):  
   if n==0 or n==1:  
     return 1  
   else:  
     return fibonacci(n-1) + fibonacci (n-2)  
   
 [fibonacci(n) for n in range(10)]  
   
 def fibonacciWithCache(n, cache={0:1, 1:1}):  
   try:  
     return cache[n]  
   except:  
     cache[n] = fibonacci(n-1) + fibonacci (n-2)  
     return cache[n]  
   
 [fibonacciWithCache(n) for n in range(10)]  
   
 # Correct Example  
 def factorial(n):  
   if n==0:  
     return 1  
   else:  
     return n * factorial(n-1)  
   
 # Correct Example, with caching  
 def factorialWithCache(n, cache={0:1}):  
   try:  
     return cache[n]  
   except KeyError:  
     cache[n] = n * factorial(n-1)  
     return cache[n]  
   
 #5! = 1*2*3*4*5  
 [factorial(n) for n in range(100)]  
 [factorialWithCache(n) for n in range(100)]  
      
 def FibonacciNonRecursive(n):  
   """Fib without recursion.  
   Note: uses assignment reversal"""  
   a, b = 0, 1  
   for i in range(1, n+1):  
     a, b = b, a+b  
   return b  
   
 [FibonacciNonRecursive(i) for i in range(1)]  
 

Comments

Popular posts from this blog

Charting Correlation Matrices in R

Attractive Confusion Matrices in R Plotted with fourfoldplot

Calculating Value at Risk (VaR) with Python or R