Plotting a parabola using Tkinter

Question

I'm a beginner, and I have just written this basic code that simply plots a parabola in a graph. Is it possible to make my code more efficient?

The process works by the creating lists of X and Y then adding range of numbers squared to the list Y and normal X to its list and then the function plot simply goes ahead and creates a range doubled + 2 the size ( because the previous range(-size, size) creates both the minus and positive values and a zero) and fills the canvas.create_line(starting X location, starting Y location, ending X location, ending Y location) statement and also creates a log.

import tkinter
from tkinter import Tk
# Adding a Tk window
root: Tk = tkinter.Tk()
root.geometry('640x480') # Configuring the resolution
# Adding the canvas to put the graph on it
CanvasNo1 = tkinter.Canvas(root, width=640, height=480)
CanvasNo1.grid()
def draw_axis(canvas_object): # a function in order to draw the horizontal and vertical lines and setting the scroll
 canvas_object.update()
 x_origin = canvas_object.winfo_width() // 2
 y_origin = canvas_object.winfo_height() // 2
 canvas_object.configure(scrollregion=(-x_origin, -y_origin, x_origin, y_origin))
 canvas_object.create_line(x_origin, 0, -x_origin, 0)
 canvas_object.create_line(0, y_origin, 0, -y_origin)
def parabola(number, size): # Calculating the parabola
 result = number * number // size
 return result
def plot(canvas_object, size, color): # The grand function to do the plotting process
 y_location = []
 x_location = []
 for each in range(-size, size+1):
 y_location.append(parabola(each, size))
 x_location.append(each)
 for each_of in range(0, size*2+2):
 if each_of <= size*2-1:
 canvas_object.create_line(x_location[each_of], -y_location[each_of], x_location[each_of+1],
 -y_location[each_of+1], fill=str(color))
 print('A line from X location of {} and Y location of {} to the X location of {} and Y location of {} was'
 ' drawn, Color = {}'.format(x_location[each_of], y_location[each_of], x_location[each_of+1],
 y_location[each_of+1], color))
 else:
 break
draw_axis(CanvasNo1)
plot(CanvasNo1, 500, 'red')
CanvasNo1.mainloop() # running the window

Answer 1

Instead of creating an empty list and appending the values to it, try using list comprehension.

so instead of

y_location = []
x_location = []
for each in range(-size, size+1):
 y_location.append(parabola(each, size))
 x_location.append(each)

try

y_location = [parabola(each,size) for each in range(-size,size+1)]
x_location = list(range(-size,size+1))

In general you can use a profiler to see which part of your code requires the largest amount of computing making it easier to improve the code. https://docs.python.org/2/library/profile.html

• Mike - SMT: The benefits of list comprehension over a for loop are small. I feel in most cases readability is more valuable than performance gain unless the date you are working with is massive.