CODEWITHSUNDEEP
pythonlistfunctioninteger
SpeakInCode43
SpeakInCode43

Reputation: 590

Function That Computes Sum of Squares of Numbers in List

I'm trying to write a function sum_of_squares(xs) that computes the sum of the squares of the numbers in the list xs. For example, sum_of_squares([2, 3, 4]) should return 4+9+16 which is 29:

Here's what I tried:

import random

xs = []

#create three random numbers between 0 and 50

for i in range(3):
    xs.append(random.randint(0,50))

def sum_of_squares(xs):

#square the numbers in the list

    squared = i ** i

#add together the squared numbers

    sum_of_squares = squared + squared + squared

    return sum_of_squares

print (sum_of_squares(xs))

Right now this always prints

12

Because it's taking i as in the number of integers in the list as opposed to the value of the integer. How do I say "multiply the value by the value of the integer" for as many integers are in the list to get the squared values?

Asking that question led me to try this:

import random

xs = []

#create three random numbers between 0 and 50

for i in range(3):
    xs.append(random.randint(0,50))

def sum_of_squares(xs):

#square the numbers in the list

    for i in (xs):
        squared = i ** i

#add together the squared numbers

        sum_of_squares = squared + squared + squared

    return sum_of_squares

print (sum_of_squares(xs))

But it doesn't seem to be squaring the values of the integers correctly - I'm not sure what it's doing. See this screenshot See Screenshot of a Visualize Python walkthrough.

Upvotes: 2

Views: 12126

Answers (3)

raghavyadav990
raghavyadav990

Reputation: 92

Right the concept first on paper.

  1. You have List of numbers.

  2. You have to parse the List, do the square and save it to some variable.

    import random

xs = []

#create three random numbers between 0 and 50

for i in range(3):
    xs.append(random.randint(0,50))

def sum_of_squares(xs):
    result = 0
    for i in xs:
        result += i*i

    return result

Upvotes: 1

Karan Nagpal
Karan Nagpal

Reputation: 341

you are doing silly mistakes. try this:

import random
xs = []
for i in range(3):
    xs.append(random.randint(0,50))

def sum_of_squares(xs):
    sum_of_squares=0  #mistake 1 : initialize sum first. you are making new sum variable in loop everytime. 
    for i in (xs):
        squared = i * i  #mistake 2 : ** is exponent and not multiply.
        sum_of_squares += squared  #mistake 3
    return sum_of_squares

print (sum_of_squares(xs))

Upvotes: 3

bulldog_in_the_dream
bulldog_in_the_dream

Reputation: 339

def sum_of_squares(xs):
    return sum(x * x for x in xs)

Upvotes: 7

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