Asterisk art in python

Question

I would like to produce this picture in python!

         *
        **
       ***
      ****
     *****
    ******
   *******
  ********
 *********
**********

I entered this:

x=1
while x<10:
 print '%10s'    %'*'*x
 x=x+1

Which sadly seems to produce something composed of the right number of dots as the picture above, but each of those dot asterisks are separated by spaced apart from one another, rather than justified right as a whole.

Anybody have a clever mind on how I might achieve what I want?

3 edits and none have corrected Asterix->Asterisk =) – Ruslan Sep 05 '11 at 12:53 — Ruslan, Sep 05 '11 at 12:53

Jeremy · Accepted Answer · 2011-09-05T13:11:30.233

13

 '%10s'    %'*'*x

is being parsed as

('%10s' % '*') * x

because the % and * operators have the same precedence and group left-to-right^[docs]. You need to add parentheses, like this:

x = 1
while x < 10:
    print '%10s' % ('*' * x)
    x = x + 1

If you want to loop through a range of numbers, it's considered more idiomatic to use a for loop than a while loop. Like this:

for x in range(1, 10):
    print '%10s' % ('*' * x)

for x in range(0, 10) is equivalent to for(int x = 0; x < 10; x++) in Java or C.

edited Sep 05 '11 at 13:11

answered Sep 05 '11 at 12:53

Jeremy

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Superb! Walla! What a nice answer! Thank you so much - works perfectly! - this is the first answer I see so I'm commenting to thank you but of course many many thanks to everyone else! My deepest appreciation of course! – Azz Sep 05 '11 at 15:01
I think you mean "Voila!", French for "There it is!", "Presto!", or "Woot, doggie!" – PaulMcG Dec 15 '11 at 04:27

wim · Answer 2 · 2011-09-07T04:31:11.643

string object has rjust and ljust methods for precisely this thing.

>>> n = 10
>>> for i in xrange(1,n+1):
...   print (i*'*').rjust(n)
... 
         *
        **
       ***
      ****
     *****
    ******
   *******
  ********
 *********
**********

or, alternatively:

>>> for i in reversed(xrange(n)):
...   print (i*' ').ljust(n, '*')
... 
         *
        **
       ***
      ****
     *****
    ******
   *******
  ********
 *********
**********

My second example uses a space character as the printable character, and * as the fill character.

The argument to ljust or rjust is the terminal width. I often use these for separating sections with headings when you have chatty debug printout, e.g. print '--Spam!'.ljust(80, '-').

score 2 · Answer 3 · answered Sep 05 '11 at 12:55

2

It's because of the operator precedence, use this one:

x=1
while x<10:
 print '%10s' % ('*'*x)
 x=x+1

answered Sep 05 '11 at 12:55

Karoly Horvath

94,607
11
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176

develerx · Answer 4 · 2011-09-05T13:07:04.063

1

print '\n'.join(' ' * (10 - i) + '*' * i for i in range(10))

edited Sep 05 '11 at 13:07

answered Sep 05 '11 at 12:54

develerx

600
5
13

score 1 · Answer 5 · answered Sep 05 '11 at 13:09

1

To be exact, as your picture ends with 10 asterisks, you need.

for i in range(1, 11):
    print "%10s"%('*' *i)

answered Sep 05 '11 at 13:09

MatthieuW

2,292
15
25

Asterisk art in python

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