I'm given a sequence tuple(range(1,5))
and I am supposed to write a recursive function with reduce to calculate the product 1*2*3*4*5 = 24.
I don't know how to do this recursively, I've tried looking here https://www.burgaud.com/foldl-foldr-python/ and understand reduce is left-fold. My none recursive implementation is simply:
def red(func, seq):
return reduce(func, seq)
red(lambda x, y: x*y, tuple(range(1,5)))
As reduce is left fold, how can I achieve this?
CodePudding user response:
To make a function recusive, you need to add a case for termination (only one element left) and the recusive call in which you make the problem smaller (go one step ahead in the sequence)
def reduce(func, seq):
if len(seq) == 1:
return seq[0]
return func(seq[0], reduce(func, seq[1:]))
print(reduce(lambda x, y: x * y, tuple(range(1, 5))))
Output:
24
If you're using python 3.10 , you should look into pattern matching for a more functional style in python.