Properly formatted multiplication table

Question

How would I make a multiplication table that's organized into a neat table? My current code is:

n=int(input('Please enter a positive integer between 1 and 15: '))
for row in range(1,n+1):
    for col in range(1,n+1):
        print(row*col)
    print()

This correctly multiplies everything but has it in list form. I know I need to nest it and space properly, but I'm not sure where that goes?

Solution 1

Quick way (Probably too much horizontal space though):

n=int(input('Please enter a positive integer between 1 and 15: '))
for row in range(1,n+1):
    for col in range(1,n+1):
        print(row*col, end="\t")
    print()

Better way:

n=int(input('Please enter a positive integer between 1 and 15: '))
for row in range(1,n+1):
    print(*("{:3}".format(row*col) for col in range(1, n+1)))

And using f-strings (Python3.6+)

for row in range(1, n + 1):
    print(*(f"{row*col:3}" for col in range(1, n + 1)))

Solution 2

Gnibbler's approach is quite elegant. I went for the approach of constructing a list of list of integers first, using the range function and taking advantage of the step argument.

for n = 12

import pprint
n = 12
m = list(list(range(1*i,(n+1)*i, i)) for i in range(1,n+1))
pprint.pprint(m)
[[1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12],
 [2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24],
 [3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36],
 [4, 8, 12, 16, 20, 24, 28, 32, 36, 40, 44, 48],
 [5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60],
 [6, 12, 18, 24, 30, 36, 42, 48, 54, 60, 66, 72],
 [7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84],
 [8, 16, 24, 32, 40, 48, 56, 64, 72, 80, 88, 96],
 [9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99, 108],
 [10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120],
 [11, 22, 33, 44, 55, 66, 77, 88, 99, 110, 121, 132],
 [12, 24, 36, 48, 60, 72, 84, 96, 108, 120, 132, 144]]

Now that we have a list of list of integers that is in the form that we want, we should convert them into strings that are right justified with a width of one larger than the largest integer in the list of lists (the last integer), using the default argument of ' ' for the fillchar.

max_width = len(str(m[-1][-1])) + 1
for i in m:
    i = [str(j).rjust(max_width) for j in i]
    print(''.join(i))

   1   2   3   4   5   6   7   8   9  10  11  12
   2   4   6   8  10  12  14  16  18  20  22  24
   3   6   9  12  15  18  21  24  27  30  33  36
   4   8  12  16  20  24  28  32  36  40  44  48
   5  10  15  20  25  30  35  40  45  50  55  60
   6  12  18  24  30  36  42  48  54  60  66  72
   7  14  21  28  35  42  49  56  63  70  77  84
   8  16  24  32  40  48  56  64  72  80  88  96
   9  18  27  36  45  54  63  72  81  90  99 108
  10  20  30  40  50  60  70  80  90 100 110 120
  11  22  33  44  55  66  77  88  99 110 121 132
  12  24  36  48  60  72  84  96 108 120 132 144

and demonstrate the elasticity of the spacing with a different size, e.g. n = 9

n=9
m = list(list(range(1*i,(n+1)*i, i)) for i in range(1,n+1))
for i in m:
    i = [str(j).rjust(len(str(m[-1][-1]))+1) for j in i]
    print(''.join(i))

  1  2  3  4  5  6  7  8  9
  2  4  6  8 10 12 14 16 18
  3  6  9 12 15 18 21 24 27
  4  8 12 16 20 24 28 32 36
  5 10 15 20 25 30 35 40 45
  6 12 18 24 30 36 42 48 54
  7 14 21 28 35 42 49 56 63
  8 16 24 32 40 48 56 64 72
  9 18 27 36 45 54 63 72 81

Solution 3

for i in range(1, 10) :
    for j in range(1, 10):
        print(repr(i*j).rjust(4),end=" ")
print()
print()

Output:

  1    2    3    4    5    6    7    8    9 

  2    4    6    8   10   12   14   16   18 

  3    6    9   12   15   18   21   24   27    

  4    8   12   16   20   24   28   32   36

  5   10   15   20   25   30   35   40   45 

  6   12   18   24   30   36   42   48   54 

  7   14   21   28   35   42   49   56   63 

  8   16   24   32   40   48   56   64   72 

  9   18   27   36   45   54   63   72   81 

or this one

for i in range(1, 11):
    for j in range(1, 11):
        print(("{:6d}".format(i * j,)), end='')
print()

the result is :

 1     2     3     4     5     6     7     8     9    10
 2     4     6     8    10    12    14    16    18    20
 3     6     9    12    15    18    21    24    27    30
 4     8    12    16    20    24    28    32    36    40
 5    10    15    20    25    30    35    40    45    50
 6    12    18    24    30    36    42    48    54    60
 7    14    21    28    35    42    49    56    63    70
 8    16    24    32    40    48    56    64    72    80
 9    18    27    36    45    54    63    72    81    90
10    20    30    40    50    60    70    80    90   100

Solution 4

Creating Arithmetic table is much simpler but i thought i should post my answer despite the fact there are so many answers to this question because no one talked about limit of table.

Taking input from user as an integer

num = int(raw_input("Enter your number"))

Set limit of table, to which extent we wish to calculate table for desired number

lim = int(raw_input("Enter limit of table"))

Iterative Calculation starting from index 1

In this, i've make use of slicing with format to adjust whitespace between number i.e., {:2} for two space adjust.

for b in range(1, lim+1):
    print'{:2} * {:2} = {:2}'.format(a, b, a*b)

Final CODE:

num = int(raw_input("Enter your number"))
lim = int(raw_input("Enter limit of table"))
for b in range(1, lim+1):
    print'{:2} * {:2} = {:2}'.format(a, b, a*b)

---

OUTPUT:

Enter your number 2
Enter limit of table 20
 2 *  1 =  2
 2 *  2 =  4
 2 *  3 =  6
 2 *  4 =  8
 2 *  5 = 10
 2 *  6 = 12
 2 *  7 = 14
 2 *  8 = 16
 2 *  9 = 18
 2 * 10 = 20
 2 * 11 = 22
 2 * 12 = 24
 2 * 13 = 26
 2 * 14 = 28
 2 * 15 = 30
 2 * 16 = 32
 2 * 17 = 34
 2 * 18 = 36
 2 * 19 = 38
 2 * 20 = 40

Solution 5

Or you could just do this (not as simplistic as the others but it works):

def main():

    rows = int(input("Enter the number of rows that you would like to create a multiplication table for: "))
    counter = 0
    multiplicationTable(rows,counter)

def multiplicationTable(rows,counter):

    size = rows + 1

    for i in range (1,size):
        for nums in range (1,size):
            value = i*nums
            print(value,sep=' ',end="\t")
            counter += 1
            if counter%rows == 0:
                print()
            else:
                counter
main()

View more solutions

Comments

[Adam Smith]

What's going on in that print function -- can you elaborate?

[Pitarou]

The (... for ... in ...) generates an iterable. The *(... for ... in ...) turns the iterable into a list of arguments to supply to print. See my answer for a discussion of how the print works. It's a fairly advanced trick, so don't worry if you don't understand it.

[martineau]

@adsmith: print() is a built-in function and the output string is being formatted using a format specification that's part of a generator expression.

[mikus]

are you sure it adds any value to the below answers? I'd say it's far less clean.

[Yehuda Katz]

I appreciate your comment. Yehuda

[Joey Baruch]

i get a "Syntax error while detecting tuple" on your Better way solution.

[John La Rooy]

@joeybaruch, are you using Python2? The question is tagged Python-3.x

[James K]

Your answer is very short and lacks context. When you have a little more reputation, you will be able to suggest improvements using comments.

[abhinav]

your code is much simpler but. it would be better if you explain a little bit further.

[Admin]

@Abhinav Thx for urs insight.

[Charnel]

Hi! Thanks for sharing answer but could you please correct the code formatting?

[Sunshine]

Sure, what do you want me to do? Get rid of the empty lines/spaces?

[sancelot]

please can you give more details about this piece of code, and what was wrong in the question asked.

[Yehuda Katz]

... and yes, I'm sure.