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+--- Thread: Recursion (/thread-22617.html)
Recursion - leodavinci1990 - Nov-20-2019
def power(n,p):
""" Return n to the power p. Works only for positive integers """
return n*power(n,p-1)
if __name__ == '__main__':
print(power(2,24)) Why does this return an error?
RE: Recursion - ichabod801 - Nov-20-2019
Well, there are two things that could cause errors that I see. One, line 5 needs to be indented or you will get an indentation error. Two, your recursive function has no stop case, so it will recurse forever, and eventually cause a recursion error. For example, take power(3, 2). That will call power(3, 1), which will call power(3, 0), which will call power(3, -1), which will call power(3, -2), and so on. You want to stop and just return n when p == 1.
RE: Recursion - ThomasL - Nov-20-2019
Read the somehow misunderstandable doc string.
""" Return n to the power p. Works only for positive integers """That positive was meant for p not n.
RE: Recursion - Malt - Nov-20-2019
(Nov-20-2019, 01:29 AM)leodavinci1990 Wrote:def power(n,p): """ Return n to the power p. Works only for positive integers """ return n*power(n,p-1) if __name__ == '__main__': print(power(2,24))
Why does this return an error?
Please check your indentation @ print part and also check for negative values for p
Try below one:
def power(n,p):
""" Return n to the power p. Works only for positive integers """
if p!=0:
return n*power(n,p-1)
return 1
if __name__ == '__main__':
r = power(2,24)
print(r)
RE: Recursion - ChislaineWijdeven - Nov-20-2019
Seems to me that as the guys above say, you need to have a closer look to your indentation @ print part; plus the negative values for p...
RE: Recursion - sumana - Nov-21-2019
def power(base,exp):
if(exp==1):
return(base)
if(exp!=1):
return(base*power(base,exp-1))
base=int(input("Enter base: "))
exp=int(input("Enter exponential value: "))
print("Result:",power(base,exp))
RE: Recursion - leodavinci1990 - Nov-27-2019
(Nov-21-2019, 11:03 AM)sumana Wrote: def power(base,exp): if(exp==1): return(base) if(exp!=1): return(base*power(base,exp-1)) base=int(input("Enter base: ")) exp=int(input("Enter exponential value: ")) print("Result:",power(base,exp))Thanks. Will make sure I follow that format next time
RE: Recursion - ThomasL - Nov-27-2019
(Nov-21-2019, 11:03 AM)sumana Wrote: def power(base,exp):
if(exp == 1):
return(base)
if(exp != 1):
return(base*power(base,exp-1))
base = int(input("Enter base: "))
exp = int(input("Enter exponential value: "))
print("Result:",power(base, exp))Above code has several problems:- What if you enter a negative exponent?
- Exponent can be 0, result would be 1
So valid version of power() looks like:
def power(base, exponent):
""" Return base to the power exponent. Works only for positive exponents"""
if exponent == 0:
return 1
elif exponent > 0:
return base * power(base, exponent - 1)
else:
raise ValueError("Exponent must be positve!")