Prime factors of number
Finds and returns the list of prime factors of a number.
- Use a
while
loop to iterate over all possible prime factors, starting with2
. - If the current
factor
exactly dividesnum
, addfactor
to thefactors
list and dividenum
byfactor
. Otherwise, incrementfactor
by one.
def prime_factors(num): factors = [] factor = 2 while (num >= 2): if (num % factor == 0): factors.append(factor) num = num / factor else: factor += 1 return factors prime_factors(12) # [2,2,3] prime_factors(42) # [2,3,7]