python - Clear a list in a function each time it's run -

i'm kind of new programming. i'm trying write algorithm in python gives prime factors of number:

factors=[] def factor(n):     in range(2,n+1):         if n%i==0:             factors.append(i)             factor(int(n/i))             break     return factors 

it works, whenever run 'factor' function again, appends populated 'factors' list - how can list clear each time function 'factor' run?

declare local variable inside function. in code you're modifying global variable factors every time call factor().

def factor(n, factors=none):     factors = [] if factors none else factors      in range(2, n + 1):         if n%i==0 , not in factors: #checks duplicates             factors.append(i)             factor(int(n / i),factors) #pass factors list in recurive call             break     return factors  factor(20) #returns [2, 5]