计算列表中数字平方和的函数

Question

我正在尝试编写一个函数sum_of_squares（xs）来计算列表xs中数字的平方和。例如，sum_of_squares（[2,3,4]）应返回4 + 9 + 16，即29：

这是我试过的：

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))

现在这总是打印

12

因为它将i视为列表中整数的数量，而不是整数的值。我怎么说“将值乘以整数的值”，因为列表中有多个整数可以得到平方值？

问这个问题让我尝试了这个：

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))

但它似乎没有正确地平衡整数的值 - 我不确定它在做什么。请参阅演练的此屏幕截图Visualize Python。

Answer 1

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

Answer 2

你犯的是愚蠢的错误。试试这个：

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))

Answer 3

首先在纸上概念这个概念。

1. 您有数字列表。

2. 你必须解析List，做正方形并将其保存到某个变量。

   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