How to write the program that prints out all the positive integer values from 1 up to the input number and each pair of numbers is flipped?

Question

My code almost works:

number = int(input("Please type in a number: "))
 
a = 2
b = 1
 
while a in range(number) or b in range(number):
    print(a)
    print(b)
    a += 2
    b += 2

with input 6 it works as it should:

Please type in a number: 6
2
1
4
3
6
5

but with input 5 it doesn’t and show the sequence 2 1 4 3 instead 2 1 4 3 5

Asked By: Denis

||

Source

Answer 1

you can do this with he help of the range function. Here is a simplified version:

acc = []
for i in range(1, number, 2):
    acc.append(i+1)
    acc.append(i)
if number % 2:  # if your number is odd then add the last number manually
    acc.append(number)

Answered By: Nullman

Answer 2

In the for loop, we are iterating over all the odd numbers up to n (1, 3, 5 …) and printing the pair of consecutive numbers ( i+1 – even no. first ). As we only wanted numbers up to n to print, we’re checking if i+1 is less than or equal to n (p.s. inside for loop the value of i is always less than or equal to n so we just needed to make sure if i+1 matches that condition too ).

n = int(input())
for i in range(1, n+1, 2):
    if i+1 <= n:
        print(i+1)
    print(i)

Answered By: Nick

Answer 3

It looks like you were very close the way you wrote it, but you didn’t add the print function at the end so you were looking at the wrong values as output. Also, use "and" instead of "or" in this case.

number = int(input("Please type in a number: "))

a = 2
b = 1

while a in range(number) and b in range(number):
    print("Original a", a)
    print("Original b", b)
    a += 2
    print("Current a", a)
    b += 2
    print("Current b", b)

Answered By: bethis

Answer 4

number = int(input("Please type in a number: "))        
a = 2       
b = 1         
count = 1       
while count <= number:
       
    count += 1
    if a <= number:
        print(a)
        a += 2
    if b <= number:
        print(b)
        b += 2

Answered By: Remy-boi

How to write the program that prints out all the positive integer values from 1 up to the input number and each pair of numbers is flipped?

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