Python Spaced Triangle

Question

I’m supposed to write a program that ends up such as this:

*     *
 *   *
  * *
   *

I have the code written for a regular one, but I’m not sure how to incorporate spaces into it.

def triangle(i, t = 0):
    if i == 0
        return 0
     else:
        print ' ' * (t + 1) + '*' * (i * 2 - 1)
        return triangle(i - 1, t + 1)

Advice?

Asked By: Thad Smith

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Source

Answer 1

Let’s label some areas in a line:

startSpaces   *   middleSpaces   *   endSpaces

For a given line you want startSpaces + 1 + middleSpaces + 1 + endSpaces to equal a constant. This constant is 2*(i+t) + 1

line 1 will have t=0 spaces before the *
the final line will have t=i spaces before the * (here I’m using the original i, I know it changes through recursion)

So can you find a pattern for startSpaces, middleSpaces and endSpaces that will give you the proper pattern?

Keep in mind that you will need an additional else if case for i==1 so that you can handle the row with only one *

Answered By: Jean-Bernard Pellerin

Answer 2

Try:

def triangle(i, t = 0):
    if i == 0:
        print (t+1) *' '+ '*'

    else:
        print ' ' * (t + 1)+ '*' + ' ' * (i * 2 - 1) + '*'
        triangle(i - 1, t + 1)

triangle(5)

this code print:

 *         *
  *       *
   *     *
    *   *
     * *
      *

Answered By: Vahid Kharazi

Answer 3

Building on @kharazi’s answer (because this reminds me of my early GWBasic programming which is what got me excited about programming as a kid):

def triangle(i, leftShape='*', rightShape='*', bottomShape='*', spaceShape=' ', t = 0):
    if i <= 0:
        print ((t+1)*spaceShape)+bottomShape+((t+1)*spaceShape)
    else:
        print (spaceShape*(t + 1))+leftShape+(spaceShape*(i*2-1))+rightShape+(spaceShape*(t + 1))
        triangle(i-1, leftShape, rightShape, bottomShape, spaceShape, t+1)

if __name__== '__main__':
    triangle(3)
    triangle(3, '\', '/')
    triangle(3, '\', '/', '~')
    triangle(5, '╚╗', '╔╝', '╚╦╝')
    triangle(5, '╚╗', '╔╝', '╚╦╝', '|')
    triangle(-2)

Produces the following output:

triangle(3)
 *     *
  *   *
   * *
    *

triangle(3, '\', '/')
      /
     /
    /
    *

triangle(3, '\', '/', '~')
      /
     /
    /
    ~

triangle(5, '╚╗', '╔╝', '╚╦╝')
 ╚╗         ╔╝
  ╚╗       ╔╝
   ╚╗     ╔╝
    ╚╗   ╔╝
     ╚╗ ╔╝
      ╚╦╝

triangle(5, '╚╗', '╔╝', '╚╦╝', '|')
|╚╗|||||||||╔╝|
||╚╗|||||||╔╝||
|||╚╗|||||╔╝|||
||||╚╗|||╔╝||||
|||||╚╗|╔╝|||||
||||||╚╦╝||||||

triangle(-2)
 *

Answered By: Jason Sperske

Answer 4

you should be using a for loop for this, recursion works but it is not the best idea to use it all the time. this is what i did:

def GioTri(i):

foo = i - 1
bar = 0

for i in range(i-1):


    print ' ' * bar + "*" + " " * (foo*2 - 1) + "*" + " " * bar
    foo = foo - 1
    bar = bar + 1


print " " * bar + "*" + " " * bar

the result of this looks like this:

*     *
 *   * 
  * *  
   *

Answered By: giovanni Rescigno

Python Spaced Triangle

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