I want to calculate the sum of the natural numbers from 1 up to an input number. I wrote this code:
number=int(input("enter a natural number"))
if number<0:
print("The number is not positive")
else:
n=0
for i in range (1,number+1):
n+=i
print(n)
But it prints multiple numbers instead. For example, if the user puts five, the program should print 15, but I get this:
1
3
6
10
15
How can I fix the code so that only 15 appears?
You have all the steps because your print statement is in your for loop.
Change it like this:
number = int(input("Enter a positive natural number: "))
if number < 0:
print("The number needs to be positive")
exit() # Stops the program
result = 0
for i in range(1, number + 1):
result += i
print(result) # We print after the calculations
There's also a mathematical alternative (see here):
number = int(input("Enter a positive natural number: "))
if number < 0:
print("The number needs to be positive")
exit() # Stops the program
print(number * (number + 1) / 2)
As I've pointed out and suggested earlier in comments, you could move the print statement out of for-loop to print the final sum.
Or you could try to use generator expression to get all number's total (sum), because we don't care the intermediate sums.
This simple sum of all up to the number in one shot.
number=int(input("enter a natural number"))
if number < 0:
print("The number is not positive")
# exit or try again <---------
else:
print(sum(range(1, number + 1))) # given 5 -> print 15
Something like this?
number = int(input("enter a natural number"))
if number < 0:
print("The number is not positive")
else:
n = 0
for i in range (1,number + 1):
n += i
print(n)
The answer to your question is that you are printing the n every time you change it. You are looking for the last answer when you run the code. This code should solve it.
number = int(input("enter a natural number"))
if number < 0:
print("The num < 0")
else:
n = 0
l = []
for i in range (0, number+1):
n+=i
l.append(n)
print(l[len(l)-1])
I am very new to python. I am trying to write a program that tests if a number is between a given range, then tells you if the number is odd or even. I am having trouble with the part that detects if it is odd or even. It seems that if it just repeats my even statement. Here is the code:
while True:
num = int(input("Please enter an integer between 1 and 50: "))
if num >= 1 and num <= 50:
for num in range (1, 50):
if (num % 2 == 0):
print("Your number is even.")
else:
print("Your number is odd.")
else:
print("Try again. Number must be 1 through 50.")
I don't think you need a for loop at all, and you forgot to indent the else part if your inner if-else:
while True:
num = int(input("Please enter an integer between 1 and 50: "))
if num >= 1 and num <= 50:
for num in range (1, 50): # not needed
if (num % 2 == 0):
print("Your number is even.")
else: # here
print("Your number is odd.")
else:
print("Try again. Number must be 1 through 50.")
for-else constructs exist (and are pretty neat), but it you're starting to learn Python, it's a story for another time.
Nope, you don't need the for loop:
while True:
num = int(input("Please enter an integer between 1 and 50: "))
if 1 <= num <= 50:
if num % 2 == 0:
print("Your number is even.")
else:
print("Your number is odd.")
else:
print("Try again. Number must be 1 through 50.")
I think you don't need for loop, Remove for loop and try again.
while True:
num = int(input("Please enter an integer between 1 and 50: "))
if num >= 1 and num <= 50:
if (num % 2 == 0):
print("Your number is even.")
else: # here
print("Your number is odd.")
else:
print("Try again. Number must be 1 through 50.")
enter image description hereEven Numbers!
Take input N from the user and print EVEN for every even number and ODD for every odd number between 1 and N.
Sample Input 1:
4
Sample Output 1:
ODD
EVEN
ODD
EVEN
You need to use the modulus opperator which is % in python to check if the number is odd or even.
N = int(input("Enter a number: "))
i = 1
while(i <= N):
if (i % 2) == 0:
print('EVEN')
else:
print('ODD')
i += 1
N = int(input())
for i in range(1,N+1):
if i%2 == 0:
print("EVEN".format(i))
else:
print("ODD".format(i))
This question already has answers here:
How can I read inputs as numbers?
(10 answers)
Closed last month.
I'm taking a class in Python and our prof wants us to write a program that prompts the user to enter an integer repeatedly until they enter 0. Then, have the program ignore all negative numbers, if any, and display the number of even integers, the number of odd integers, the sum of the even integers, the sum of the odd numbers, and the number of positive integers.
I've been trying and trying to do this program in small parts. However, I always end up getting stuck. I've started over about 5 times now and I would really appreciate if someone were to point me in the right direction.
So far, I have this:
num_str = input("Input an integer (0 terminates):")
num_int=int(num_str)
even_count=0
odd_count=0
even_sum=0
odd_sum=0
while num_int !=0:
num_str = input("Input an integer (0 terminates):")
num_int=int(num_str)
for num_int in num_str:
if num_int%2 == 0:
even_count += 1
else:
odd_count +=1
print("")
print("Sum of odds:", odd_sum)
print("Sum of evens:", even_sum)
print("Even count:", even_count)
print("Odd count:", odd_count)
print("Total positive int count:")
I know it's not much and I'm missing a whole lot, but I just wrote what I know needs to be included so far. I keep getting stuck because the program keeps giving me errors. Any sort of help is very appreciated because I have really no idea where to start!
Your code has a few problems, but they're small:
1) You're asking for numbers before your main loop, so the first integer entered wouldn't be summed (lines 1 and 2)
2) It doesn't make sense for you to have a for loop like the one in your main loop. What you were doing is trying to check for each character in the string. Just not what you'd want.
3) To ignore negative numbers, just check if they're less than 0 and continue (break the loop) if they are.
4) You were using indentation with 3 spaces. It's probably your text editor's fault, so try to configure it to use 4 spaces instead, which is the standard in Python.
5) Convention says there should be a space around operators.
6) Positive integer count is just another simple counter.
All that revised, this is what your code should look like:
num_int = None
even_count = 0
odd_count = 0
even_sum = 0
odd_sum = 0
while num_int != 0:
num_str = input("Input an integer (0 terminates):")
num_int = int(num_str)
if num_int < 0:
continue # Continue the loop and go back to asking input
# If the loop reaches this point we know it's a positive number, so just add one
positive_count += 1
if num_int % 2 == 0:
even_count += 1
even_sum += num_int
else:
odd_count +=1
odd_sum += num_int
print("")
print("Sum of odds:", odd_sum)
print("Sum of evens:", even_sum)
print("Even count:", even_count)
print("Odd count:", odd_count)
print("Total positive int count:", positive_count)
You should declare a variable
total = 0
to count the number of integers the user has entered.
It's also more readable to have a
while True:
loop that breaks when the input is zero, instead of the loop you have.
Within the loop, you should
break
if the input is equal to 0,
continue
if the input is less than 1, increment even_count and add to even_sum if the input is even,
even_count += 1
even_sum += num
and increment the odd_count and odd_sum otherwise,
odd_count += 1
odd_sum += num
finally, you should increment the total:
total += 1
Also make sure to change the last line of your code to:
print("Total positive int count:", total)
to display the total
Your end result should look like this:
even_count = 0
odd_count = 0
even_sum = 0
odd_sum = 0
total = 0
while True:
num = int(input("Input an integer (0 terminates): "))
if num == 0:
break
if num < 1:
continue
if num % 2 == 0:
even_count += 1
even_sum += num
else:
odd_count += 1
odd_sum += num
total += 1
print("")
print("Sum of odds:", odd_sum)
print("Sum of evens:", even_sum)
print("Even count:", even_count)
print("Odd count:", odd_count)
print("Total positive int count:", total)
try this
userInput = None
oddSum = 0
oddCount = 0
evenSum = 0
evenCount = 0
while(userInput != 0):
userInput = int(input("Enter a number: "))
if(userInput > 0):
if(userInput % 2 == 0):
evenSum += userInput
evenCount += 1
elif(userInput % 2 != 0):
oddSum += userInput
oddCount += 1
print("even numbers: {} sum: {}".format(evenCount, evenSum))
print("odd numbers: {} sum: {}".format(oddCount, oddSum))
to ignore negative numbers, you could have them put it in agian, with an if loop like this
if (num_str>0):
num_str = input("That was not an even number, input an integer (0 terminates)")
Then to add them you would have to add the integer version of num_str to it like this
odd_sum += int(num_str)
here's some code for you to try
num_str = input("Input an integer (0 terminates):")
num_int=int(num_str)
even_count=0
odd_count=0
even_sum=0
odd_sum=0
total = even_count + odd_count
while num_int !=0:
num_str = input("Input an integer (0 terminates):")
num_int=int(num_str)
if num_int < 0:
num_str = input("Input an integer greater than 0.")
for num_int in num_str:
num_int = int(num_str)
if num_int % 2 == 0 and not num_int == 3 and not num_int == 0:
even_count += 1
even_sum = even_sum + num_int
elif not num_int == 0:
odd_count +=1
odd_sum = odd_sum + num_int
total = even_count + odd_count
print("")
print("Sum of odds:", odd_sum)
print("Sum of evens:", even_sum)
print("Even count:", even_count)
print("Odd count:", odd_count)
print("Total positive int count:", total)
val = []
inpt = None
evensm, oddsm = 0, 0
while inpt != 0:
inpt = int(input("Enter a number: "))
val.append(inpt)
for i in val:
if i % 2 == 0:
evensm += i
else:
oddsm += i
print("Sum of even integers is", evensm)
print("Sum of odd integers is", oddsm)
Or if you don't prefer using lists:
oddsm = 0
evensm = 0
while 1:
inpt = int(input("Enter a number: "))
if inpt == 0:
break
elif inpt % 2 == 0:
evensm += inpt
else:
oddsm += inpt
print("Sum of odd integers is", oddsm)
print("Sum of even integers is", evensm)
Write a Python program to take input of positive numbers, with an appropriate prompt, from the user until the user enters a zero. Find total number of odd & even numbers entered and sum of odd and even numbers. Display total count of odd & even numbers and sum of odd & even numbers with appropriate titles.
sumOdd =0
sumEven = 0
cntOdd =0
cntEven = 0
while True :
no = int(input("enter a number (0 for exit)"))
if no < 0 :
print("enter positive no......")
elif no == 0 :
break
elif no % 2 == 0 :
cntEven = cntEven+1
sumEven = sumEven + no
else :
cntOdd = cntOdd+1
sumOdd = sumOdd + no
print ("count odd == ",cntOdd)
print ("sum odd == ",sumOdd)
print ("count even == ",cntEven)
print ("sum even == ",sumEven)
Write a Python program to take input of a positive number, say N, with an appropriate prompt, from the user. The user should be prompted again to enter the number until the user enters a positive number. Find the sum of first N odd numbers and first N even numbers. Display both the sums with appropriate titles.
n = int(input("enter n no.... : "))
sumOdd =0
sumEven = 0
for i in range (n) :
no = int(input("enter a positive number : "))
if no > 0 :
if no % 2 == 0 :
sumEven = sumEven + no
else :
sumOdd = sumOdd + no
else :
print("exit.....")
break
print ("sum odd == ",sumOdd)
print ("sum even == ",sumEven)
I have to write a program that tells the user the factorial of any integer between 1 and 15 while using the while loop. I wrote the code below and the output gives me endless factorials/numbers.. Do you know what I did wrong? Thank you!
Update: I realized that I should use "while" for what num isn't, so I now have this code below, but it still says invalid syntax for the second "while".
# take input from the user
num = int(input("Please enter a number from 1 to 15: "))
factorial = 1
# check if the number is negative, positive or zero
while num < 0:
num = int(input("Negative numbers don't have factorials! Please enter a number between 1 and 15: ")
while num > 15:
num = int(input("Please enter a number between 1 and 15! ")
if num == 0:
print("The factorial of 0 is 1")
else:
for i in range(1,num + 1):
factorial = factorial*i
print("The factorial of",num,"is",factorial)
I would do this:
from math import factorial as factorial
while True:
num = int(input("Please enter a number from 1 to 15: "))
if 1 <= num <= 15:
fact = factorial(num)
print 'the factorial of {n} is {f}'.format(n=num, f=fact)
else:
num = int(input("Please enter a number from 1 to 15: "))
You missed a closing parenthesis:
while num > 15:
num = int(input("Please enter a number between 1 and 15! "))
^ here
you have missed the braces at the end of int() funtion
# take input from the user
num = int(input("Please enter a number from 1 to 15: "))
factorial = 1
# check if the number is negative, positive or zero
while num < 0:
num = int(input("Negative numbers don't have factorials! Please enter a number between 1 and 15: ")) # brace was missing
while num > 15:
num = int(input("Please enter a number between 1 and 15! ")) # brace was missing
if num == 0:
print("The factorial of 0 is 1")
else:
for i in range(1,num + 1):
factorial = factorial*i
print("The factorial of",num,"is",factorial)
You might have meant like the below in order to loop until you get correct input:
# take input from the user
num = int(input("Please enter a number from 1 to 15: "))
factorial = 1
while(True):
if num < 0:
num = int(input("Negative numbers don't have factorials! Please enter a number between 1 and 15: ")) # brace was missing
continue
if num > 15:
num = int(input("Please enter a number between 1 and 15! ")) # brace was missing
continue
if num == 0:
print("The factorial of 0 is 1")
else:
for i in range(1,num + 1):
factorial = factorial*i
print("The factorial of",num,"is",factorial)
break