Python program to draw a bar chart using turtle

Prerequisite: Turtle Programming Basics

Turtle is a Python feature like a drawing board, which lets us command a turtle to draw all over it! We can use functions like a turtle.forward(…) and turtle.right(…) which can move the turtle around. Turtle is a beginner-friendly way to learn Python by running some basic commands and viewing the turtle do it graphically. It is like a drawing board that allows you to draw over it. The turtle module can be used in both object-oriented and procedure-oriented ways.

To draw, Python turtle provides many functions and methods i.e. forward, backward, etc. Some commonly used methods are:

• forward(x): moves the pen in the forward direction by x unit.
• backward(x): moves the pen in the backward direction by x unit.
• right(x): rotate the pen in the clockwise direction by an angle x.
• left(x): rotate the pen in the anticlockwise direction by an angle x.
• penup(): stop drawing of the turtle pen.
• pendown(): start drawing of the turtle pen.

Turtle can be used to draw any static shape (Shape that can be drawn using lines). We all know that

Approach:

• Import the turtle library.
• Create a function, say drawBar() that takes a turtle object, a height value, and a color name and perform the following steps:
  • The function draws vertical rectangles of a given height and fixed width (say 40).
  • The function fills the rectangle with the given color name.
• Initialize a list having some numerical values (data for the bar graph).
• Initialize a turtle instance.
• Set up the window and call the drawBar() for each value of the list with the created turtle instance and any color of your choice.
• After completing the above steps, close the turtle instance.

Below is the implementation of the above approach:

Python3

# Python program to draw a turtle
import turtle

# Function that draws the turtle
def drawBar(t, height, color):

    # Get turtle t to draw one bar
    # of height

    # Start filling this shape
    t.fillcolor(color)
    t.begin_fill()
    t.left(90)
    t.forward(height)
    t.write(str(height))
    t.right(90)
    t.forward(40)
    t.right(90)
    t.forward(height)
    t.left(90)

    # stop filling the shape
    t.end_fill()

# Driver Code

xs = [48, 117, 200, 96, 134, 260, 99]
clrs = ["green", "red", "yellow", "black",
        "pink", "brown", "blue"]

maxheight = max(xs)
numbers = len(xs)
border = 10

# Set up the window and its
# attributes
wn = turtle.Screen()
wn.setworldcoordinates(0 - border, 0 - border,
                       40 * numbers + border,
                       maxheight + border)

# Create tess and set some attributes
tess = turtle.Turtle()
tess.pensize(3)

for i in range(len(xs)):

    drawBar (tess, xs[i],
             clrs[i])

wn.exitonclick()

Output: