how can i achieve this ? I'm trying to have an Input that will print out all the numbers in sequential order using python

codingembryo 0
Viewed 41

Desired OutputThis is what I want my output to be.

What I have now.

rows = int(input("Please Enter a Number  : "))

for I in range(1, rows + 1):

    for j in range(1, I + 1):

        print('*', end = '  ')

    print()

But This is what I want my output to be

Enter any number : 21
Output
1
2 3
4 5 6
7 8 9 10
11 12 13 14 15
16 17 18 19 20 21

Right Angle triangle output thing.

Its been driving me nuts. Please help :) Thanks in anticipation

python
2 Answers

Hellor, here's your solution for your problem

rows = int(input("Please Enter a Number  : "))
count = 1
number = 1
while number <= rows:
    for i in range(count):
        print(number, end=" ")
        number += 1
    count += 1
    print("\n", end="")

Since you always need to add one number per line you need a variable to store the number of numbers to print (Here count). You also need a variable to count the current number that you increment for each iteration of count (here number) and you stop only when the current number is greater then the input (Here rows)

Yasha_ops0

Ignoring the triangle part, the first step is to print all the numbers:

rows = int(input("Please Enter a Number  : "))
for num in range(1, rows + 1):
  print(num, end=" ")

From there we want to add an if to also print a new line if our number is

  • equal to 'rows', or
  • the number we expect to be at the end of the current level

Since the number of items in each row is an arithmetic progression (i.e. each level is +1 longer than the level above it) we can calculate the number at the end of each level using the formula for summing an arithmetic progression:

number_at_end_of_level = level * (level + 1) / 2

The simple explanation for this formula is that you're finding the average number of items in each level by averaging the first and last level average = (level + 1) / 2. Because we know the average, we can then multiply that by the number of levels to get the total.

So putting it all together the solution is:

rows = int(input("Please Enter a Number  : "))
level = 1
for num in range(1, rows + 1):
  print(num, end=" ")
  number_at_end_of_level = level * (level + 1) / 2
  if num == number_at_end_of_level or num == rows:
    level += 1
    print()

Alternatively, if you don't want to do the calculation, you can just count how many items you've printed in the current level and print a new line when that count is equal to the current level number:

rows = int(input("Please Enter a Number  : "))
level = 1
current_level_count = 0
for num in range(1, rows + 1):
  print(num, end=" ")
  current_level_count += 1
  if current_level_count == level or num == rows:
    level += 1
    current_level_count = 0
    print()
Rob Croft0
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