How do I make a triangle of numbers using python loops?

Question

I am trying to achieve this

0 1 2 3 4 5 6 7 8 9
  0 1 2 3 4 5 6 7 8
    0 1 2 3 4 5 6 7
      0 1 2 3 4 5 6 
        0 1 2 3 4 5
          0 1 2 3 4
            0 1 2 3
              0 1 2
                0 1
                  0

And I'm getting close but now I'm stuck. Here is my current code

def triangle():
    n = 9
    numList = [0,1,2,3,4,5,6,7,8,9]
    for i in range(10):
        for i in numList:
            print(i, end="  ")
        print()
        numList[n] = 0
        n -= 1
triangle()

And this is the current output

0  1  2  3  4  5  6  7  8  9  
0  1  2  3  4  5  6  7  8  0  
0  1  2  3  4  5  6  7  0  0  
0  1  2  3  4  5  6  0  0  0  
0  1  2  3  4  5  0  0  0  0  
0  1  2  3  4  0  0  0  0  0  
0  1  2  3  0  0  0  0  0  0  
0  1  2  0  0  0  0  0  0  0  
0  1  0  0  0  0  0  0  0  0  
0  0  0  0  0  0  0  0  0  0  

So I'm there in a round about way, except, its backwards, and there is 0's instead of spaces

Answer 1

You can try this code:

def triangle():
    for i in range(10):
        print i * "  ",
        for j in range(10 - i):
            print j,
        print    

triangle()

The code is almost self explaining.

Online example is here

Answer 2

interesting puzzle, you could try this:

n = range(0,10)    #set your range
while len(n)<20:   #loop until it exhausts where you want it too
  print ''.join(str(e) for e in n[0:10])  #print as a string!
  n = [' ']+n      #prepend blank spaces

here is an example

You could apply the same logic to your attempt. Basically I add a space to the beggining of N after each loop and then print only the first ten elements. The way I print the list is a little clunky because I am joining, I need to change each element to a string.

Answer 3

The other solutions are fine, but life becomes a little easier with numpy 's arange and the overloaded * operator for strings. Python's built-ins are very powerful.

for i in range(11):
    print ' ' * i + ''.join(str(elt) for elt in np.arange(10 - i))