CODEWITHSUNDEEP
python
TaTa
TaTa

Reputation: 41

Sum of numbers starting from 1 (python)

I started to learn Python and I am stucked in lesson. I need to create program, where you at first asked for insert digit (you insert for example "5") and result should be sum of digits starting from 1 up to this digit you inserted (in this example 1+2+3+4+5). I created a program which is listing numbers up to inserted digit, but I cannot finish it - to create sum of those digits. Here is my code:

print ("Insert the digit")
digit = int(input())
i = 0
while i < (digit):
    i = i + 1
    print (i)

Upvotes: 1

Views: 450

Answers (5)

nitishagar
nitishagar

Reputation: 9413

You can try following:

i = 0
total = 0
while i < digit:
    i = i + 1 # can be i += 1
    total = total + i # can be total += i
print (total)

range function can also be used. You can read about this.

Upvotes: 3

Jon Clements
Jon Clements

Reputation: 142226

As others have pointed out, you're not keeping a running total, you can however use a maths trick here, eg:

n = int(input('Enter digit: '))
print('Total sum is:', int(n*(n/2 + .5)))

This'll be far more efficient for larger n... so instead of building a generator and summing each at a time, you can use that formula to calculate in constant time any value of n.

Upvotes: 5

WorldSEnder
WorldSEnder

Reputation: 5054

A really pythonic way would be to do the following:

print ("Insert the digit")
digit = int(input())
i = 0
while i < (digit):
    i = i + 1
    print (i)
summed = sum(range(digit+1))
print(summed)

Note: You should not use the variable name sum because that is a reserved symbol (language intern)

Upvotes: 0

Hackaholic
Hackaholic

Reputation: 19763

you can use sum with range:

my_sum = sum(range(1,digit+1))

range will give you list of integers, syntax range([start],stop) ,it will ends always one less, see the demo below

demo:

>>> range(10)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> range(1,10)
[1, 2, 3, 4, 5, 6, 7, 8, 9]

demo for sum:

>>> my_num = range(1,10)
>>> my_num
[1, 2, 3, 4, 5, 6, 7, 8, 9]
>>> sum(my_num)
45

Upvotes: 3

Bhargav Rao
Bhargav Rao

Reputation: 52181

You can also try

print ("Insert the digit")
digit = int(input())
print(sum(range(digit+1)))

Here range is a function which will list all the numbers from 0 to digit and sum will calculate the total of them

Upvotes: 0

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