更改 matplotlib.pyplot 点的颜色

Question

这是我写的情节代码：

import matplotlib.pyplot as plt

Y = [ 1 , 2 , 3 ]
X = [ 1 , 2 , 4 ]
vocabulary = [1 , 2 , 3]

plt.scatter(X , Y)
for label, x, y in zip(vocabulary, X, Y):
    if(label == 1):
        plt.annotate('', xy=(x, y), xytext=(0, 0), color='red' , textcoords='offset points')
    elif(label == 1):
        plt.annotate('', xy=(x, y), xytext=(0, 0), color='green' , textcoords='offset points')
    elif(label == 1):
        plt.annotate('', xy=(x, y), xytext=(0, 0), color='blue' , textcoords='offset points')
    else :
        plt.annotate('', xy=(x, y), xytext=(0, 0), color='black' , textcoords='offset points')
plt.show()

我试图根据数组中的值更改颜色，vocabulary 如果 1 则将数据点着色为红色，如果 2 则将数据点着色为绿色，如果 3 则将数据点着色为蓝色，否则将数据点着色为黑色。但对于所有点，每个点的颜色都设置为蓝色。如何根据 的当前值对数据点着色vocabulary？

上面的代码产生：

Answer 1

您可以制作一个颜色字典并在散点图中查找它，如下所示

%matplotlib inline
import matplotlib.pyplot as plt

Y = [ 1 , 2 , 3 ,6]
X = [ 1 , 2 , 4 ,5]
vocabulary = [1 , 2 , 3, 0]
my_colors = {1:'red',2:'green',3:'blue'}

for i,j in enumerate(X):
    # look for the color based on vocabulary, if not found in vocubulary, then black is returned.
    plt.scatter(X[i] , Y[i], color = my_colors.get(vocabulary[i], 'black'))

plt.show()

结果是

Answer 2

您刚刚犯了一点复制和粘贴错误。只是对你的风格的评论：当使用颜色列表时，你可以避免这么多如果，所以：

colors=[red,green,blue,black]

进而 ：

plt.annotate('', xy=(x, y), xytext=(0, 0), color=colors[max(3,label)] , textcoords='offset points')

你的代码必须是这样，你总是这样写elif label=1，这绝对没有意义：

import matplotlib.pyplot as plt

Y = [ 1 , 2 , 3 ]
X = [ 1 , 2 , 4 ]
vocabulary = [1 , 2 , 3]

plt.scatter(X , Y)
for label, x, y in zip(vocabulary, X, Y):
    if(label == 1):
        plt.annotate('', xy=(x, y), xytext=(0, 0), color='red' , textcoords='offset points')
    elif(label == 2):
        plt.annotate('', xy=(x, y), xytext=(0, 0), color='green' , textcoords='offset points')
    elif(label == 3):
        plt.annotate('', xy=(x, y), xytext=(0, 0), color='blue' , textcoords='offset points')
    else :
        plt.annotate('', xy=(x, y), xytext=(0, 0), color='black' , textcoords='offset points')
plt.show()