Matplotlib — Line Plots Explained in Detail

Matplotlib made easy in 30 days

Image for post Photo by Anne Nygrd on Unsplash

Quick recap:

Introduction to the basics
How to fit Multiple Subplots in a single window
How to deal with Figure & Axes
Complete Guide to Scatter plots

Today’s topic:

It is the most used one ?Line plots?, widely across various industries like finance (stock forecasting), biology (decay forecasting), sports (team comparisons) and many more.

Commands for line plots
Multiline plots
Adding annotations to each point
Customizing markers, line styles & legends

we use the following command

import matplotlib.pyplot as pltplt.plot(x,y)

Let?s draw a simple line plot

import numpy as npx = np.arange(1,11)y = np.random.random(10)plt.plot(x,y)plt.show() Image for post Basic Line Plot

One more:

x = np.linspace(1,10,1000)y = np.sin(x)plt.plot(x,y)plt.show() Image for post

Customizing line plots with Markers, Linestyles, Annotations & Legends

Image for post fig, (ax1, ax2, ax3) = plt.subplots(1,3, figsize = (12,4))x = np.arange(1,11)y1 = np.random.random(10)y2 = np.random.random(10)y3 = np.random.random(10)ax1.plot(x, y1)ax1.set_title(‘Plain Line plot’)ax2.plot(x, y2, marker = ‘o’)ax2.set_title(‘Line plot with markers’)ax3.plot(x, y3, marker = ‘o’, linestyle = ‘:’)ax3.set_title(‘Line plot with markers & linestyle’)plt.show()

Let?s try annotating each point with its (x,y) coordinates, this can be tricky because we need to specify the coordinates at which the annotations should appear:

Image for post Generating annotations using a simple For loopplt.figure(figsize = (10,10))x = np.arange(1,11)y = np.random.random(10)y = np.random.random(10)plt.plot(x,y, marker = ‘*’, linestyle = ‘–‘)for i in range(len(x)): xi = “{:.1f}”.format(x[i]) yi = “{:.1f}”.format(y[i]) s = str(“P(” + str(xi) + ‘,’ + str(yi) + ‘)’ ) plt.text(x[i] + 0.03, y[i] + 0.03, s)

Multi-line plot & addition of legends:

When there are two or more lines, it?s always a good practice to use legends to specify each line.

Image for post fig, (ax1, ax2, ax3) = plt.subplots(1,3, figsize = (12,4))x = np.arange(1,11)y1 = np.random.random(10)y2 = np.random.random(10)y3 = np.random.random(10)ax1.plot(x, y1, marker = ‘*’)ax1.plot(x, y2, marker = ‘*’)ax1.set_title(‘Double Line plot’)ax2.plot(x, y1, marker = ‘*’, linestyle = ‘:’)ax2.plot(x, y2, marker = ‘*’, linestyle = ‘:’)ax2.plot(x, y3, marker = ‘*’, linestyle = ‘:’)ax2.set_title(‘2 or more Lines’)ax3.plot(x, y1, marker = ‘*’, label = ‘line1’)ax3.plot(x, y2, marker = ‘*’ , label = ‘line2’)ax3.plot(x, y3, marker = ‘*’, linestyle = ‘:’, label = ‘line3’)ax3.set_title(‘Multiple lines with legends’)plt.legend()plt.show()