Как найти сумму нечетных чисел питон

This should work for you:

def sumoddnum(s):
  return sum(0 if int(i) % 2 == 0 else int(i) for i in s)

or if you want to keep your first attempt, you should iterate through your str then check the condition on every int of character:

def sumoddnum(s):
    total= 0
    for i in s:
        if int(i) % 2 == 1:
            total += int(i)
    return total 
print(sumoddnum('12345'))

answered Dec 1, 2019 at 7:17

I like using a regex approach here. We can apply the regex pattern [13579] to the input string, then use a list comprehension on the resulting list of odd digits to find the sum:

num = "123"
odds = re.findall(r'[13579]', num)
sum = sum(int(odd) for odd in odds)
print("the sum is: " + str(sum))

This prints:

The sum is: 4

answered Dec 1, 2019 at 7:24

Your first approach does not work because what you’re actually adding to the sum are ‘indices’ of s not it’s elements. What could have work is changing your for loop to run over elements instead of their positions. Then keep in mind that elements of a string are characters so a conversion to the int is required. This can be done with built-in int function whenever the character actually represents a digit.

def sumoddnum(s):
    total= 0
    for i in s:
        if int(i) % 2 == 1:
            total += int(i)
    return total 

Now at this point you may wonder

what a long function for such a simple task!

and you’ll be absolutely right. Luckily, Python comes with comprehensions which allow us to shorten some of the for loops and built-in sum function which purpose is kinda self-explanatory but what you need to remember that it takes iterables as its input.

The result you may get will be something like this:

def sumoddnum(s):
    return sum(int(i) for i in s if int(i) % 2 == 1)

With Python 3.8 you can also make use of brand new walrus operator:

def sumoddnum(s):
    return sum(num for i in s if (num := int(i)) % 2 == 1)

The problem with your second approach is already explained by the Python interpreter itself. You’ve converted your string to the integer, and there’s no built-in way too loop over integers. You’ll need to find and implement your own way to loop over integer’s digits (hint: use remainder modulo 10).

answered Dec 1, 2019 at 7:48

The reason your program is not working is because of the line:

for i in range(len(str)):

here, you are taking all values of i from 0 to the length of the string (exclusive of length).

This means, you are adding up all the odd numbers from 0 to the length of the String.

Instead do this:

for i in str:

this will give you each character in the string as i. Now:

i = int(i)

will convert it to int.

Finally :

if i%2 == 1: 
    total+=i

the final code will be:

def sumoddnum(s):
    total= 0
    for i in s:
        i = int(i)
        if i % 2 == 1:
            total += i
    return total 
print(sumoddnum('12345'))

answered Dec 1, 2019 at 7:54

def sumoddnum(s):
    total= 0
    for i in s:
        i = int(i)
        if i % 2 == 1:
            total += i
    return total 
print(sumoddnum('12345'))

if you use ‘range(len(s))’ in for loop instead of ‘s’, it will give you [0,1,2,3,4] which is 0 to length of the ‘12345.

Therefore, it is required to change the range by just s, then it will give you [‘1′,’2′,’3′,’4′,’5’] which is char elements of string ‘12345’.

Don’t forget to change the type of i to int!

answered Dec 1, 2019 at 7:47

vdtes­t
[29K]

4 месяца назад 

#Произвадим ввод библиотек математики и рандома
from math import*
from random import*
#Здесь производим вывод надписи на экран и попутно элемент для вычисления
n=int(input("Введите количество элементов в массиве: " ))
#Вводим пустой массив
arr=[]
#Производим ввод массива (я взял массив от -15 до 15)
for i in range(n):
    arr.append(randint(-15,15))
    #Производим показ получившегося массива
print(arr)
min=arr[0]
#Зададим в 2 единицы для вычисления
#Одну из них берем за 0
k=0
j=1
#Пишем условие для j
x=j%2==0
#В последней строке не уверен что она правильная

задан 27 ноя 2021 в 14:30

Пишем сумму значений массива в нечетных индексах:

Sum=0
for j in range(n):
    if arr[j]%2==1:
        Sum+=arr[j]
print(Sum)