How can I write a factorial based on the number?-CodePudding

So I;m trying to write a function file(s:int, filn:str) -> None that writes the value of n! to a file with the specified filename.

n! is n the number to the extent which the factorial will be calculated.

For example:

file(10, 'test.out')
# test.out
3628800

Here is my attempt at the code so far, which clearly doesn't work at all, what should I change?

filn = 100

def file(s:int, filn:str):
    s = open(filn)
    q = s.read()
    for i in range(1,s 1):
        return (q * i)

print(file(10, 'data'))

CodePudding user response：

Calculate factorial value and when write it into a file.

def file(x: int, file_name: str) -> None:
    factorial = 1
    for i in range(2, x   1):
        factorial *= i
    with open(file_name, 'w') as file:
        file.write(str(factorial))

This function writes value of x! into file with file_name name.

CodePudding user response：

Unless you insist on calculating the factorial yourself, you should probably also use the math library for efficiency.

Using Ratery's answer with the math library:

from math import factorial

def file(x: int, file_name: str) -> None:
    with open(file_name, 'w') as file:
        file.write(str(factorial(x)))