gistfile1.py

from math import *

#get the input numbers and returns them as a list
def inputget():

    #get a string of input, and separate it into numbers
    inputs = input("Enter numbers separated by spaces: ").split(' ')

    #create an empty list
    output_int = []

    #iterate through the string, casting each character as an
    #integer and appending the list each time
    for letter in inputs:

        #if it's a digit cast it as a number and append the list
        if letter.isdigit():
            output_int.append(int(letter))
            
    return output_int

#sums the values in the list passed in
def getlistsum(listin):

    total = 0
    
    #iterate through list adding the values as they come
    for number in listin:
        total += number

    return total

#returns a list of the differences between the items in 'listin' and the 'mean'
def getMeanDiff(listin, mean):

    diffsList = []

    for num in listin:
        diffsList.append(num-mean)

    return diffsList

#squares each item in 'listin' and creates a new list of the result
def squareList(listin):

    sqList = []

    for num in listin:
        sqList.append(pow(num, 2))

    return sqList

#input numbers
numbers  = inputget()

#amount of them
numNums = len(numbers)

#sum of the input
sumNums = getlistsum(numbers)

#mean of the inputs
meanNums = float(sumNums/numNums)

#the diferences between thi inputs and the mean
diffList = getMeanDiff(numbers,meanNums)

#the squares of he differences
sqList = squareList(diffList)

#the sum of the squares
sumSq = getlistsum(sqList)

#finally the std deviation
deviation = pow(sumSq/numNums,0.5)

#show result
print("Standard Deviation: {0:.4f}".format(deviation))