Show values ​​in grid using matplotlib

Question

I am trying to create heatmaps for some data, and my code is shown below:

data = [['basis', 2007, 2008], [1, 2.2, 3.4], [2, 0, -2.2], [3, -4.1, -2.5], [4, -5.8, 1.2], [5, -5.4, -3.6], [6, 1.4, -5.9]] x_header = data[0][1:] y_header = [i for i in range(1, 13)] data=data[1:] for i in range(len(data)): data[i] = data[i][1:] arr = np.array(data) fig, ax = plt.subplots() #heatmap = plt.pcolor(arr, cmap = 'RdBu') norm = MidpointNormalize(midpoint=0) im = ax.imshow(data, norm=norm, cmap=plt.cm.seismic, interpolation='none') ax.set_xticks(np.arange(arr.shape[1]), minor=False) ax.set_yticks(np.arange(arr.shape[0]), minor=False) ax.xaxis.tick_top() ax.set_xticklabels(x_header, rotation=90) ax.set_yticklabels(y_header) fig.colorbar(im) plt.show() 

It generates an image.

I also want to show the values ​​inside the grid. Is there any way to do this?

Answer 1

Of course, just do something like:

 import matplotlib.pyplot as plt import numpy as np data = np.random.random((4, 4)) fig, ax = plt.subplots() # Using matshow here just because it sets the ticks up nicely. imshow is faster. ax.matshow(data, cmap='seismic') for (i, j), z in np.ndenumerate(data): ax.text(j, i, '{:0.1f}'.format(z), ha='center', va='center') plt.show() 

However, shortcuts are hard to see, so you might need a window around them:

 import matplotlib.pyplot as plt import numpy as np data = np.random.random((4, 4)) fig, ax = plt.subplots() # Using matshow here just because it sets the ticks up nicely. imshow is faster. ax.matshow(data, cmap='seismic') for (i, j), z in np.ndenumerate(data): ax.text(j, i, '{:0.1f}'.format(z), ha='center', va='center', bbox=dict(boxstyle='round', facecolor='white', edgecolor='0.3')) plt.show() 

In addition, in many cases, ax.annotate more useful if ax.text . This is much more flexible in how you can position the text, but it is also more complex. Take a look at the examples here: http://matplotlib.org/users/annotations_guide.html