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# Plot a Horizontal line in Matplotlib

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, Using axhline()

The axhline() function in pyplot module of matplotlib library is used to add a horizontal line across the axis.

Syntax: matplotlib.pyplot.axhline(y, color, xmin, xmax, linestyle)

Parameters:

• y: Position on Y 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

 `# importing library``import` `matplotlib.pyplot as plt`` ` `# specifying horizontal line type``plt.axhline(y ``=` `0.5``, color ``=` `'r'``, linestyle ``=` `'-'``)`` ` `# rendering the plot``plt.show()`

Output:

### Plotting multiple horizontal lines

To plot multiple horizontal lines, use the axhline() method multiple times.

## Python

 `# importing the module``import` `matplotlib.pyplot as plt`` ` `# plotting line within the given range``plt.axhline(y ``=` `.``5``, xmin ``=` `0.25``, xmax ``=` `0.9``)`` ` `# line colour is blue``plt.axhline(y ``=` `3``, color ``=` `'b'``, linestyle ``=` `':'``)`` ` `# line colour is white``plt.axhline(y ``=` `1``, color ``=` `'w'``, linestyle ``=` `'--'``)`` ` `# line colour is red``plt.axhline(y ``=` `2``, color ``=` `'r'``, linestyle ``=` `'dashed'``)    ``   ` `# adding axis labels    ``plt.xlabel(``'x - axis'``)``plt.ylabel(``'y - axis'``)`` ` `# displaying the plot``plt.show()`

Output:

 `# importing the module``import` `matplotlib.pyplot as plt`` ` `# plotting line within the given range``plt.axhline(y ``=` `.``5``, xmin ``=` `0.25``, xmax ``=` `0.9``)`` ` `# line colour is blue``plt.axhline(y ``=` `3``, color ``=` `'b'``, linestyle ``=` `':'``, label ``=` `"blue line"``)`` ` `# line colour is white``plt.axhline(y ``=` `1``, color ``=` `'w'``, linestyle ``=` `'--'``, label ``=` `"white line"``)`` ` `# line colour is red``plt.axhline(y ``=` `2``, color ``=` `'r'``, linestyle ``=` `'dashed'``, label ``=` `"red line"``)    ``   ` `# adding axis labels    ``plt.xlabel(``'x - axis'``)``plt.ylabel(``'y - axis'``)`` ` `# plotting the legend``plt.legend(bbox_to_anchor ``=` `(``1.0``, ``1``), loc ``=` `'upper center'``)`` ` `# displaying the plot``plt.show()`