title: the meaning of python3.x syntax
body: <p>I want to make a pascal triangle from python script. and this is my syntax that I get from <a href="http://web.programminghub.io/#/program/Python" rel="nofollow">web.programminghub.io</a></p>
  
  <pre><code>size = int(input("Enter the size of the triangle: ")) 
  tri=[]
  
  #creates a pascal triangle of size n
  def pascal(n):
     """Prints out n rows of Pascal's triangle.
     It returns False for failure and True for success."""
     row = [1]
     k = [0]
     for x in range(max(n,0)):
        tri.append(row)
        row=[l+r for l,r in zip(row+k,k+row)]
     return n&gt;=1
  
  
  #prints the pascal triangle with correct spacing to 
  #represent a triangle
  def print_pascals_triangle(triangle):
      largest_element = triangle[-1][len(triangle[-1]) // 2]
      element_width = len(str(largest_element))
      def format_row(row):
          return ' '.join([str(element).center(element_width) 
  for element in row])
      triangle_width = len(format_row(triangle[-1]))
      for row in triangle:
          print(format_row(row).center(triangle_width)) 
  pascal(size)
  
  print_pascals_triangle(tri)
  </code></pre>
  
  <p>the problem is, no explanation for every single of line from this script code. so can someone explain every line of this syntax meaning.</p>