Putting integers in tabular form without whitespace in Python

Question

Sorry that I ask this here, because this seems really elementary and is most likely asked before. However, I have been searching and trying for hours and I couldn't find anything that helped me out. I want to write a program that asks for an upper bound and returns a table with pairs of numbers (m,n) such that the sum of of divisors of n (excluding n) equals m, and vice versa.

Now I wrote the following

bound = int(input('upper bound = '))
l = len(str(bound))
for x in range(1,l):
    print(' ', end='')
print('m', end='  ')
for y in range(1,l):
    print(' ', end='')
print('n', end='')
for i in range(1,bound):
    for j in range (1, bound):
        if j == i:
            break
        som_i = 0
        som_j = 0
        for k in range(1,i):
            if i % k == 0:
                som_i += k
        for l in range(1,j):
            if j % l == 0:
                som_j += l
        if som_i == j and som_j == i:
            print('{:{prec}d}'.format(j, prec = l).rstrip(''), end="")
            print('{:{prec}d}'.format(i, prec = l+2).lstrip(''), end="")

The problem is that I want the pair to be displayed in tabular form side to side and with the right indentation, depending on the length of the number. Whatever I tried (I read so many treads with similar questions already) Python keeps adding a whitespace.

Can anyone help me out on this? I am really new to Python and I cannot figure this out myself. If relevant, I am using version 3.6.

EDIT:

For example, when I run the program I get:

upper bound = 300
  m    n        
220
284

while I would like to get

upper bound = 300
  m    n        
220  284

And similar for larger inputs.

EDIT2 My question is not a duplicate, since i already tried adding

end=""

which did not work.

Possible duplicate of [How can I suppress the newline after a print statement?](https://stackoverflow.com/questions/12102749/how-can-i-suppress-the-newline-after-a-print-statement) — mkrieger1, Jun 04 '18 at 17:20
It's not a duplicate, I tried that already before posting and that method did not work. — Václav Mordvinov, Jun 04 '18 at 17:34
Edit your question to include the `end=""`, and to show the (reproducible) results of running it that way. — abarnert, Jun 04 '18 at 17:36

score 2 · Accepted Answer · answered Jun 04 '18 at 17:43

The first problem is that you're not using end='' after printing the j value, but you apparently already know about that. You also are using it after printing the n header, which you don't want.

Your edited version fixes the missing end='' after the j print, but then adds one after the i print, which, again, you don't want.

I'm not sure you understand what end='' means, so you're just putting it into your code randomly. That isn't going to get you very far. You can read the docs for print, but the short version is: use end='' when you're printing something that isn't supposed to be the end of a line, like that m header and j value, but don't use it when you're printing something that is supposed to be the end of a line, like that n header and i value.

The second problem is that l is just way too big. After for l in range(1,j):, it's going to be the same value as j, which means it's going to be 219, so you're going to print that 220 filled out to 219 characters, and that 284 filled out to 221 characters. So, unless your terminal is more than 446 characters wide, it's going to scroll across multiple lines and look like a mess. I think what you may want here is to use 3 and 5.

Or, maybe, you have some other variable that's supposed to be 3, and you want to use (let's call that variable x) x and x+2 instead of l and l+2. But I don't see any obvious candidates in your code.

So:

# ... unchanged lines
print('n') # no end='' here
# ... more unchanged lines
        # using 3 and 5 instead of l and l+2, and adding end=''
        print(('{:{prec}d}'.format(j, prec = 3)).rstrip(''), end='')
        print(('{:{prec}d}'.format(i, prec = 5)).lstrip(''))

And now, the output is:

upper bound = 300
  m    n
220  284

Thank you very much for your detailed answer, I really appreciate your help. And again sorry if my question was not clear but I'm really new to Python so I had a hard time explaining this properly. There were a few mistakes with the 'end' command. I thought I understood it properly, but I didn't. The big mistake however, was by choosing 'l' somewhere in in a for loop, while I defined 'l' as the length of the input. — Václav Mordvinov, Jun 04 '18 at 18:06

Putting integers in tabular form without whitespace in Python

1 Answers1