How To Set Matplotlib Axis Format

In a function graph, sometimes the independent variable X and the dependent variable Y correspond exponentially, so the scale of the coordinate axis needs to be set to a logarithmic scale. This article will tell you how to implement it in Matplotlib by resetting the axis format with examples.

1. How To Set Matplotlib Axis Format.

1. Matplotlib uses the xscale or yscale attribute of the axes object to format the axes.

   # set the first axes y axis format to 'log'.
   axes_left.set_yscale('log')

2. You can use the axes object’s attribute spines ( a python dictionary object ) to set the figure’s border’s style such as color, linewidth, etc.

   # set the y-axis color and line width.
   axes_left.spines['left'].set_color('red')
   axes_left.spines['left'].set_linewidth(3)

3. In the below example, there are 2 figures. The left figure’s axis has been modified, and the right figure’s axis is normal.

   import matplotlib.pyplot as plt
   
   import numpy as np
   
   def matplotlib_set_axis_format():
       
       # divide the figure canvas to 1 row and 2 columns.
       fig, axes = plt.subplots(1, 2, figsize=(10,4))
       
       # get the first axes object.
       axes_left = axes[0]
       
       # get the second axes object.
       axes_right = axes[1]
       
       # calculate x array.
       x = np.arange(0, 10) 
       
       # calculate the y values.
       y = np.exp(x) 
          
       
       axes_left.set_title('Logarithmic scale ( log y axis )')
       axes_left.set_xlabel('x-axis')
       axes_left.set_ylabel('y-axis')
       
       # set the first axes y axis format to 'log'.
       axes_left.set_yscale('log')
       
       # set the y-axis color and line width.
       axes_left.spines['left'].set_color('red')
       axes_left.spines['left'].set_linewidth(3)
       
       # set the x-axis color and line width.
       axes_left.spines['bottom'].set_color('green')
       axes_left.spines['bottom'].set_linewidth(2)
   
       # hide the right and top border.
       axes_left.spines['right'].set_color(None)    
       axes_left.spines['top'].set_color(None)
   
           
       # call the plot function to draw the figure. 
       axes_left.plot(x,y) 
       
       axes_right.set_title('Normal scale ( normal y axis )')
       axes_right.set_xlabel('x-axis')
       axes_right.set_ylabel('y-axis')
       axes_right.plot(x,y) 
       
       # show the figure. 
       plt.show()  
       
       
   if __name__ == '__main__':
       
       matplotlib_set_axis_format()

4. When you run the above example, it will create the below picture.