GCD and LCM functions in Python for several numbers

gcd_and_lcm.py

# Greatest common divisor of 1 or more numbers.
from functools import reduce


def gcd(*numbers):
    """
    Return the greatest common divisor of 1 or more integers

    Examples
    --------
    >>> gcd(5)
    5
    >>> gcd(30, 40)
    10
    >>> gcd(120, 40, 60)
    20
    """
    # Am I terrible for doing it this way?
    from math import gcd

    return reduce(gcd, numbers)

# Least common multiple is not in standard libraries? It's in gmpy, but this
# is simple enough:


def lcm(*numbers):
    """
    Return lowest common multiple of 1 or more integers.

    Examples
    --------
    >>> lcm(5)
    5
    >>> lcm(30, 40)
    120
    >>> lcm(120, 40, 60)
    120
    """
    def lcm(a, b):
        return (a * b) // gcd(a, b)

    return reduce(lcm, numbers, 1)

# Assuming numbers are positive integers...

http://rik0-techtemple.blogspot.com/2010/09/nice-functional-lcm-in-python.html

This is the simplest lcm formula I could find. Thanks!

good, thanks :)

For python3 support, maybe you should add (it's also compatible with python2 )

from functools import reduce

For python3 use
from math import gcd
fraction gcd has been deprecated.

what does *numbers look like? What is the expected parameter?

Thanks for it!!

thank you!

Excellent! How elegant it is.

For case of n no's in python 2.7

>>> from fractions import gcd
>>> def get_gcd(*nos):
...     return reduce(gcd,nos)
... 
>>> get_gcd(120,40,60)
20
>>> get_gcd(30,40)
10

thanks very much for the sharing

Concatenated everything for the convenience.

from functools import reduce
from fractions import gcd

def lcm(a, b):
    return a * b / gcd(a, b)

def lcms(*numbers):
     return reduce(lcm, numbers)

def gcds(*numbers):
     return reduce(gcd, numbers)

Last update for Python 3:

from functools import reduce
from math import gcd

def lcm(a, b):
    return int(a * b / gcd(a, b))

def lcms(*numbers):
    return reduce(lcm, numbers)

@kovalevcon Why int(float division) instead of int division?

Easy! Just do:
import math
ans = math.gcd(8, 10)
For lcm, do:
import math
ans = math.lcm(8, 10)
or:
import math
gcd_ans = math.gcd(8, 10)
lcm_ans = 8 * 10 / gcd_ans
I got it from this site:
https://www.geeksforgeeks.org/gcd-in-python/
Check it out!

I think there should be floordiv instead of truediv in your lcm

import math

def lcm(a, b):
    return int(a * b / math.gcd(a, b))
print(lcm(2, 6))

Great code! Can you plz explain me how does GCD works in your program?

Use this line of code to take LCM. Its fast and give you LCM of multiple numbers

import numpy as np
divisor_list = [3,4,5,6,7,2]
int(np.lcm.reduce(divisor_list))

Use this line of code to take LCM. Its fast and give you LCM of multiple numbers

import numpy as np
divisor_list = [3,4,5,6,7,2]
int(np.lcm.reduce(divisor_list))

Thanks alot

It's not mentioned here, but this is the Euclidean algorithm for computing the GCD: https://en.wikipedia.org/wiki/Euclidean_algorithm

Love how short the code is!

def find_gcd(a,b):
gcd = 1
for i in range(1,a+1):
if a%i==0 and b%i==0:
gcd = i
return gcd

first = int(input('Enter first number: '))
second = int(input('Enter second number: '))

print('HCD of %d and %d is %d' %(first, second, find_gcd(first, second)))

lcm = first * second / find_gcd(first, second)
print('MCM of %d and %d is %d' %(first, second, lcm))
print("azam")