使用matplotlib

Question

我米試圖產生用於一些數據熱圖顯示在網格中的值和我的代碼如下所示：

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() 

它生成圖像

我還想要在網格中顯示值。有沒有辦法做到這一點？

Answer 1

當然，僅僅這樣做：

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() 

然而，標籤是很難看到，所以您可能希望他們周圍的框：

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() 

此外，在很多情況下，ax.annotate更有用ax.text。在如何放置文本方面它更加靈活，但也更加複雜。看看這裏的例子：http://matplotlib.org/users/annotations_guide.html