做反向對角線在熱圖

Question

我想在圖像上所看到下面給出做一些白色，

只設置反向對角線白色的在左邊。我無法將它們設置爲白色。該圖表採用整數值，我不知道白色對應的整數值是什麼。

謝謝！

被修改：

下面是代碼;

import math 
from matplotlib import pyplot as plt 
from matplotlib import cm as cm 
import pylab 
import numpy as np 
from matplotlib.collections import LineCollection 

class HeatMap: 
    def __init__(self, selectedLines): 
     self.selectedLines = selectedLines 


    def getHeapMap(self): 
     figure = plt.figure() 

     if len(self.selectedLines) != 0: 

      self.map = self.createTestMapData(len(self.selectedLines),    len(self.selectedLines)) 


      maxValueInMap = self.findMaxValueInMap(self.map) 

      x = np.arange(maxValueInMap + 1) 
      ys = [x + i for i in x] 
      ax = figure.add_subplot(111) 
      ax.imshow(self.map, cmap=cm.jet, interpolation='nearest') 

      ''' 
      Left side label of the chart is created according to selected values 
      from a checkbox group. 
      ''' 
      leftSideLabelSize = len(self.selectedLines) 
      sideLabels = [] 
      for line in self.selectedLines: 
       sideLabels.append(line.text()) 
      pos = np.arange(leftSideLabelSize) 
      ''' 
      Left side labels are set with the code below. 
      ''' 
      pylab.yticks(pos, sideLabels) 
      plt.xticks(pos, sideLabels) 
      self.numrows, self.numcols = self.map.shape 
      ax.format_coord = self.format_coord 

      line_segments = LineCollection([zip(x, y) for y in ys], 
       linewidths=(0.5, 3, 1.5, 2), 
       linestyles='solid') 
      line_segments.set_array(x) 
      axcb = figure.colorbar(line_segments) 

     return figure 

    def format_coord(self, x, y): 
     col = int(x + 0.5) 
     row = int(y + 0.5) 
     if col >= 0 and col < self.numcols and row >= 0 and row < self.numrows: 
      z = self.map[row, col] 
      return 'x=%1.4f, y=%1.4f, z=%1.4f' % (x, y, z) 
     else: 
      return 'x=%1.4f, y=%1.4f' % (x, y) 

    def createTestMapData(self, xSize, ySize): 
     resultMap = 10 * np.random.rand(xSize, ySize) 
     #Setting reverse diagonal is here. Now it is set with zero but it gives blue. 
     # I want it to be set as white 
     for index in range(0, int(math.sqrt(resultMap.size))): 
      resultMap[index][((math.sqrt(resultMap.size) - 1) - index)] = 0 
     return resultMap 

    def findMaxValueInMap(self, map): 
     return np.amax(map) 

這些值是此刻隨機生成的。上面的代碼給出了一個gui，

Answer 1

你可以使自己的顏色表，或調整現有的:)

下面是上述情節的代碼，並解釋相關的評論：

import matplotlib 
from pylab import * 
import numpy as np 

#Create test data with zero valued diagonal: 
data = np.random.random_sample((25, 25)) 
rows, cols = np.indices((25,25)) 
data[np.diag(rows, k=0), np.diag(cols, k=0)] = 0 

#Create new colormap, with white for zero 
#(can also take RGB values, like (255,255,255): 
colors = [('white')] + [(cm.jet(i)) for i in xrange(1,256)] 
new_map = matplotlib.colors.LinearSegmentedColormap.from_list('new_map', colors, N=256) 

pcolor(data, cmap=new_map) 
colorbar() 
savefig('map.png') 
show() 

另外，你可以掩蓋你的數據，並設置一個面具顏色：

#Create test data: 
data = np.random.random_sample((25, 25)) 
#Create a diagonal mask: 
mask = np.diag(np.ones(25)) 
#Apply mask to data: 
masked_data = ma.masked_array(data, mask) 
#Set mask color to white: 
cm.jet.set_bad(color='white', alpha=None) 
#for this to work we use pcolormesh instead of pcolor: 
pcolormesh(masked_data, cmap=cm.jet) 
colorbar() 
show() 

這實質上產生相同的結果，但可能滿足您的需求更好，因爲你可以將任何單元格設置爲白色，也白不上的彩條顯示出來（見上彩條的最底部）：

Answer 2

該顏色表是由cmap論點ax.imshow()定義。您已使用jet色彩映射，因此您有cmap=cm.jet，這只是matplotlib中的衆多built-in color maps之一。你可以選擇一個或定義你自己的，適合你的口味。