In this tutorial, we will learn how to create a line chart using Matplotlib in Python. Matplotlib's plot function allows us to create both linear and curved lines while offering customization options such as color, width, and marker size.

Creating a Basic Line Chart

Let's start by plotting a simple line chart.

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 9, 10)  
y = 2 * x
plt.plot(x, y, "b-")
plt.show()

Explanation

  1. Importing Libraries: We import Matplotlib and set it as plt.

import matplotlib.pyplot as plt

  1. Defining Data:

x = [1,2,3,4,5,6,7,8,9,10]
y = [1,2,3,4,5,6,7,8,9,10]

  1. Plotting the Graph: Using plt.plot() with x on the horizontal axis and y on the vertical axis.

plt.plot(x, y)
plt.show()

Customizing Line Style and Color

You can modify the appearance of the line by specifying color and style.

import matplotlib.pyplot as plt

x = [1,2,3,4,5,6,7,8,9,10]
y = [1,2,3,4,5,6,7,8,9,10]

plt.plot(x, y, "r--")  # Red dashed line
plt.show()

 

Adding Titles

To set the title of the plot:

plt.title('Plot using Python')

You can also customize the title's font and alignment:

plt.title("Left title", fontdict={'family': 'serif', 'color' : 'darkblue','weight': 'bold','size': 16}, loc='left')
plt.title("Center title", fontdict={'family': 'monospace', 'color' : 'red','weight': 'bold','size': 16}, loc='center')
plt.title("Title right", fontdict={'family': 'fantasy', 'color' : 'black','weight': 'bold','size': 16}, loc='right')

Labeling Axes

To label the x-axis and y-axis:

plt.xlabel('X-axis values')
plt.ylabel('Y-axis values')

With custom styles:

plt.xlabel('X-axis values', family='serif', color='r', weight='normal', size=16, labelpad=6)
plt.ylabel('Y-axis values', family='serif', color='r', weight='normal', size=16, labelpad=6)

Adding Grid to the Plot

You can enable the grid using:

plt.grid(True)

Line Customization Options

Line Colors

Matplotlib provides built-in color aliases:

Alias Color
b blue
g green
r red
c cyan
m magenta
y yellow
k black
w white

Line Styles

Matplotlib supports different line styles:

Line Style Description
- Solid Line
-- Dashed Line
: Dotted Line
-. Dash-Dot Line

Adjusting Line Width

You can modify the line width using the linewidth parameter:

plt.plot(x, y, "r--", linewidth=2)

Or use the abbreviated version:

plt.plot(x, y, "r--", lw=2)

Example:

import matplotlib.pyplot as plt

x = [1,2,3,4,5,6,7,8,9,10]
y = [1,2,3,4,5,6,7,8,9,10]

plt.plot(x, y, "r--", linewidth=5)
plt.title('Graph using Python')
plt.xlabel('X-axis values')
plt.ylabel('Y-axis values')

plt.show()

Conclusion

In this tutorial, we explored how to create and customize line charts in Matplotlib. In the next section, we will explore more advanced customization options and graphing techniques.

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