Daily Challenge #169 - Christmas Tree

def xmas_tree(height):
  rows = []
  # if height is 5, we count from 1 to 5
  for r in range(1, height+1):
    # append spaces and then *'s:
    #   - number of spaces: directly inverse to row depth
    #   - number of *'s: twice the row depth minus one
    #      (to make an odd total so the center is a '*')
    rows.append(' '*(height-r) + '*'*(r*2-1))
  return '\n'.join(rows)

print(xmas_tree(1))
print(xmas_tree(2))
print(xmas_tree(3))
print(xmas_tree(4))
print(xmas_tree(5))
print(xmas_tree(10))

*

 *
***

  *
 ***
*****

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

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

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

def christmas_tree(height = 0)
  star_string = ""
  height.times do |level|
    number_of_stars = 2 * (level + 1) - 1
    stars = '*' * number_of_stars
    star_string << " " * (height - level)  << stars << "\n"
  end
  star_string
end

print christmas_tree(5)
print christmas_tree(10)

const christmasTree = height => {
  const width = height * 2 - 1
  return Array
    .from(
      { length: height },
      (v, i) => {
        const stars = i + 1
        return '*'.repeat(stars * 2 - 1)
          .padStart(width / 2 + stars)
          .padEnd(width)
      }
    )
    .join('\n')
}

import sys


def christmas_tree(height):
    '''
    Outputs a Christmas tree of the correct height.
    '''
    try:
        height = int(height)
    except:
        raise TypeError('Height must be of type int. Actual type: {}'.format(type(height)))
    if height is None or height < 1 or height > 100:
        raise ValueError('Height must contain a value greater than 0')

    level = 0
    while level < height:
        stars = '*' * calculate_num_of_stars(level)
        stars = stars.center(height * 2)
        print(stars)
        level += 1


def calculate_num_of_stars(level):
    '''
    Calculates the correct number of stars that must be output.
    '''
    return 2 * (level + 1) - 1


if len(sys.argv) > 1:
    height = sys.argv[1]
    print(christmas_tree(height))