How to plot a vertical line in python

Matplotlib is a popular python library used for plotting, It provides an object-oriented API to render GUI plots. Plotting a horizontal line is fairly simple, The following code shows how it can be done.

Making a single vertical line

Method #1: Using axvline()

This function adds the vertical lines across the axes of the plot

Syntax: matplotlib.pyplot.axvline(x, color, xmin, xmax, linestyle)

Parameters:

• x: Position on X axis to plot  the line, It accepts integers.
• xmin and xmax: scalar, optional, default: 0/1.  It plots the line in the given range
• color: color for the line, It accepts  a string. eg ‘r’ or ‘b’ .
• linestyle: Specifies the type of line, It accepts a string. eg ‘-‘, ‘–‘, ‘-.’, ‘:’, ‘None’, ‘ ‘, ”, ‘solid’, ‘dashed’, ‘dashdot’, ‘dotted’

Python3

import matplotlib.pyplot as plt

import numpy as np

plt.figure(figsize = (10, 5))

plt.axvline(x = 7, color = 'b', label = 'axvline - full height')

plt.show()

Output:

Method #2: Using vlines()

matplotlib.pyplot.vlines() is a function used in the plotting of a dataset. In matplotlib.pyplot.vlines(), vlines is the abbreviation for vertical lines. What this function does is very much clear from the expanded form, which says that function deals with the plotting of the vertical lines across the axes.

Syntax: vlines(x, ymin, ymax, colors, linestyles)

Parameters:

• x: Position on X axis to plot  the line, It accepts integers.
• xmin and xmax: scalar, optional, default: 0/1.  It plots the line in the given range
• color: color for the line, It accepts  a string. eg ‘r’ or ‘b’ .
• linestyle: Specifies the type of line, It accepts a string. eg ‘-‘, ‘–‘, ‘-.’, ‘:’, ‘None’, ‘ ‘, ”, ‘solid’, ‘dashed’, ‘dashdot’, ‘dotted’

Python3

import matplotlib.pyplot as plt

import numpy as np

xs = [1, 100]

plt.figure(figsize = (10, 7))

plt.vlines(x = 37, ymin = 0, ymax = max(xs),

           colors = 'purple',

           label = 'vline_multiple - full height')

plt.show()

 
 Output:

Method #3: Using plot() 

The plot() function in pyplot module of matplotlib library is used to make a 2D hexagonal binning plot of points x, y.

Syntax : plot(x_points, y_points, scaley = False)

Parameters:

• x_points/y_points: points to plot
• scalex/scaley: Bool, These parameters determine if the view limits are adapted to the data limits

Python3

import matplotlib.pyplot as plt

plt.figure(figsize = (10, 5))

plt.plot((0, 0), (0, 1), scaley = False)

plt.show()

 
 Output:

Plotting multiple lines with the legend

The below methods can be used for plotting multiple lines in Python.

Method #1: Using axvline() 

Python3

import matplotlib.pyplot as plt

import numpy as np

plt.figure(figsize = (10, 5))

plt.axvline(x = 7, color = 'b', label = 'axvline - full height')

plt.axvline(x = 7.25, ymin = 0.1, ymax = 0.90, color = 'r',

            label = 'axvline - % of full height')

plt.legend(bbox_to_anchor = (1.0, 1), loc = 'upper left')

plt.show()

Output:

Method #2: Using vlines()

Python3

import matplotlib.pyplot as plt

import numpy as np

xs = [1, 100]

plt.figure(figsize = (10, 7))

plt.vlines(x = [37, 37.25, 37.5], ymin = 0, ymax = max(xs),

           colors = 'purple',

           label = 'vline_multiple - full height')

plt.vlines(x = [38, 38.25, 38.5], ymin = [0, 25, 75], ymax = max(xs),

           colors = 'teal',

           label = 'vline_multiple - partial height')

plt.vlines(x = 39, ymin = 0, ymax = max(xs), colors = 'green',

           label = 'vline_single - full height')

plt.vlines(x = 39.25, ymin = 25, ymax = max(xs), colors = 'green',

           label = 'vline_single - partial height')

plt.legend(bbox_to_anchor = (1.0, 1), loc = 'up')

plt.show()

Output:

How do I make a vertical line in Python?

How do you plot a vertical line in pandas?

How do you plot vertically?

How do you plot a line in Python?