How do you add numbers from 1 to n in python?

I'm trying to write a program to add up number from 1 to n. I've managed to get it to print the numbers several times but not add them all. It keeps on just adding two of the numbers.

My 1st attempt is:

def problem1_3(n):
    my_sum = 0
    # replace this pass (a do-nothing) statement with your code
    while my_sum <= n:
        my_sum = my_sum + (my_sum + 1)
    print() 
    print(my_sum)

How can I fix this problem?

asked May 10, 2017 at 19:45

3

I don't understand why everyone keeps making everything complex. Here is my simple solution

n = int(input())
print(n * (n + 1) // 2)

answered Feb 22, 2020 at 3:41

Akshat TamrakarAkshat Tamrakar

1,8272 gold badges11 silver badges16 bronze badges

2

You can do it with one line, where you create a list of integers from 0 to n and sums all the elements with sum function

def problem1_3(n):
    return sum(range(n+1))

answered May 10, 2017 at 19:57

3

That's where I use "math" to solve problems like this. There is a formula for solving this problem: n * (n+1) / 2.

The code I would write:

def sum(n):
  return n*(n+1)//2

Mike Rapadas

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answered Jun 3, 2021 at 12:42

ahmedgahmedg

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You need 2 different variables in your code -- a variable where you can store the sum as you iterate through the values and add them (my_sum in my code), and another variable (i in my code) to iterate over the numbers from 0 to n.

def problem1_3(n):
    my_sum = 0
    i=0
    #replace this pass (a do-nothing) statement with your code
    while i <= n:
        my_sum = my_sum + i
        print(my_sum)
        i+=1
    return my_sum

You are using the my_sum variable in your code to both store the sum and iterate through the numbers.

ayhan

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answered May 10, 2017 at 20:23

0

This one line do the job :

sum(range(1, n+1))

answered Feb 8, 2018 at 14:04

answered Oct 24, 2018 at 13:27

The sum of numbers from 1 to n will be greater than n. For example, the sum of numbers from 1 to 5 is 15 which is obviously greater than 5. Your while loop terminates prematurely. You need to maintain a separate counter for the loop.

answered May 10, 2017 at 20:14

HeshamHesham

111 silver badge2 bronze badges

Actually, I have tried a lot of that type of Programs In Jupyter Notebook you may use these:

n = int(input("Enter the Number: "))
print(n * (n + 1) // 2)

And Also You may try this code:

def problem1_3(n):
return n + problem1_3(n-1) if n > 1 else 1

And Also You may try it

def f(a):
return (a + 1) * (abs(a) + 2 * (a <= 0)) // 2

answered Dec 10, 2020 at 16:41

Real programmers use recursion (and hopes for a not too big n since there is no tail call optimization in Python):

def problem1_3(n):
    return n + problem1_3(n-1) if n > 1 else 1

answered May 10, 2017 at 20:28

JohanLJohanL

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1

so it will be more optimal

def f(a):
    return (a + 1) * (abs(a) + 2 * (a <= 0)) // 2

answered Sep 11, 2018 at 9:26

yoloyyoloy

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1

print("Sum =",sum(range(int(input("Enter a number\n"))+1)))

answered Oct 24, 2018 at 12:55

1

THIS WHILE LOOP ACTUALLY WORKS:

def main():

n = int(input('Enter a number:'))              

while n <= 1:
    n = int(input('Please input a new number'))

total = 0
my_sum = 0
while (n - 1) >= total:
    total = total + 1
    my_sum += total
    print(my_sum)
    
    
return 

main()

answered Mar 8, 2021 at 3:20

1

These lines worked for me in Python

def summation(num): 
sumX = 0
for i in range(1, num + 1):
    sumX = sumX + i
return sumX

summation(3) #You place the num you need here

As well as these:

def summation(num):
    return sum(range(1, num+1))

summation(3) #You place the num you need here

answered Jul 10, 2021 at 22:40

How about you try it using a "While Loop":

def problem1_3(n):
my_sum = 0
while my_sum <= n:
    print(my_sum,end=" ")  # end = " " keeps from starting a new line
    my_sum = my_sum + 1
print(my_sum) 

answered Jun 28, 2017 at 12:15

n = input("Enter Number to calculate sum")
n = int (n)
#average = 0.
#sum = 0
sum = 0.
for num in range(0,n+1,1):
    sum = sum+num
print("SUM of first ", n, "numbers is: ", sum )

# Print sum of numbers from 1 to N inclusive

def sum2N(N):
    r = 0
    for i in range(N+1):
        #for i in range(0,N+1,1):
        #r+=i
        r=r+i
    return(r)

print(sum2N(10))

answered Apr 29, 2019 at 9:04

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