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Matplotlib.pyplot.gca() in Python
  • Difficulty Level : Basic
  • Last Updated : 21 Apr, 2020

Matplotlib is a library in Python and it is numerical – mathematical extension for NumPy library. Pyplot is a state-based interface to a Matplotlib module which provides a MATLAB-like interface.

matplotlib.pyplot.gca() Function

The gcf() function in pyplot module of matplotlib library is used to get the current Axes instance on the current figure matching the given keyword args, or create one.

Syntax: matplotlib.pyplot.gca(\*\*kwargs)

Parameters: This method does not accepts any parameter.
Returns: This method does not return any value.

Below examples illustrate the matplotlib.pyplot.gca() function in matplotlib.pyplot:



Example #1:




# Implementation of matplotlib function
import matplotlib.pyplot as plt
import numpy as np
import matplotlib.gridspec as gridspec
from mpl_toolkits.axes_grid1 import make_axes_locatable
  
  
plt.close('all')
arr = np.arange(100).reshape((10, 10))
fig = plt.figure(figsize =(4, 4))
im = plt.imshow(arr, 
                interpolation ="none",
                cmap ="plasma")
  
divider = make_axes_locatable(plt.gca())
cax = divider.append_axes("left"
                          "15 %",
                          pad ="30 %")
  
plt.colorbar(im, cax = cax)
  
fig.suptitle('matplotlib.pyplot.gca() function\
Example\n\n', fontweight ="bold")
plt.show()

Output:

Example #2:




# Implementation of matplotlib function
import matplotlib.pyplot as plt
from matplotlib.tri import Triangulation
from matplotlib.patches import Polygon
import numpy as np
   
  
def update_polygon(tri):
      
    if tri == -1:
        points = [0, 0, 0]
    else:
        points = triang.triangles[tri]
          
    xs = triang.x[points]
    ys = triang.y[points]
    polygon.set_xy(np.column_stack([xs, ys]))
   
   
def motion_notify(event):
      
    if event.inaxes is None:
        tri = -1
    else:
        tri = trifinder(event.xdata, event.ydata)
          
    update_polygon(tri)
    plt.title('matplotlib.pyplot.gca() function \
    Example\n\n Potion number : % i' % tri, 
              fontweight ="bold")
      
    event.canvas.draw()
  
ang = 3
radi = 8
radii = np.linspace(0.25, 0.95, radi)
res = np.linspace(0, 4 * np.pi, ang)
res = np.repeat(res[..., np.newaxis], radi, axis = 1)
res[:, 1::2] += np.pi / ang
  
x = (radii * np.cos(2 * res)).flatten()
y = (radii * np.sin(2 * res)).flatten()
triang = Triangulation(x, y)
triang.set_mask(np.hypot(x[triang.triangles].mean(axis = 1),
                         y[triang.triangles].mean(axis = 1))
                < 0.25)
   
trifinder = triang.get_trifinder()
   
plt.subplot(111, aspect ='equal')
plt.triplot(triang, 'go-')
polygon = Polygon([[0, 0], [0, 0]],
                  facecolor ='r')
update_polygon(-1)
  
plt.gca().add_patch(polygon)
plt.gcf().canvas.mpl_connect('motion_notify_event',
                             motion_notify)
   
plt.show()

Output:

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