Matplotlib散点-值错误：RGBA序列的长度应为3或4

Question

我正试图为我的功能绘制一个图表，但我始终收到以下错误：

ValueError: RGBA sequence should have length 3 or 4

当我只有6种形状的时候，代码工作得很好，但是现在我把它增加到了10种，它就不工作了？

如果我用c = np.random.random((100, 4))而不是c=y生成c=c，它会工作，但是每个数据点都有不同的颜色。

我的代码是：

features = ["Number of Sides", "Standard Deviation of Number of Sides/Perimeter",
      "Standard Deviation of the Angles", "Largest Angle"]

features1 = ["Label"]

def Build_Data_Set():

    data_df = pd.DataFrame.from_csv("AllMixedShapes2.csv")

    #This line randomly shuffles the data so that the different types of training data get
    #mixed up randomly to prevent the data being skewed
    data_df = data_df.reindex(np.random.permutation(data_df.index))
    X = np.array(data_df[features].values)

    data_df2 = pd.DataFrame.from_csv("AllMixedShapes2.csv")
    y = np.array(data_df2[features1].replace("Circle",0).replace("Equilateral Triangle",1)
             .replace("Right Angle Triangle",2).replace("Acute Triangle",3)
             .replace("Obtuse Triangle",4).replace("Square",5)
             .replace("Parallelogram",6).replace("Rectangle",7)
             .replace("Pentagon",8).replace("Seal",9).values.tolist())
return X,y

def SVC_Analysis():

    test_size = 300
    X,y = Build_Data_Set()

    clf = svm.SVC(kernel = 'rbf', C = 1.0)
    clf.fit(X[:test_size],y[:test_size])

    correct_count = 0

    for x in range(1, test_size+1):
            if clf.predict(X[-x])[0] == y[-x]:
                correct_count += 1

    print("Accuracy:", (correct_count/test_size) * 100.00)


    data_df = pd.DataFrame.from_csv("AllMixedShapes2.csv")
    X1 = np.array(data_df[features2].values)
    y1 = np.array(data_df[features3].values)
    #w = clf.coef_[0]
    #a = -w[0] / w[1]
    xx = np.linspace(0,5)
    yy = np.linspace(0,185)

    h0 = plt.plot(xx,yy, "k-", label="non weighted")

    plt.scatter(X1[:, 0],y1, c=y, cmap=plt.cm.Paired)
    plt.ylabel("Maximum Angle (Degrees)")
    plt.xlabel("Number Of Sides")
    plt.title('Shapes')
    plt.legend()
    plt.show()

SVC_Analysis()

My csv file for reference looks like

据我所知，这个问题与c=y, cmap=plt.cm.Paired)有关，但我不能确定，也找不到解决办法。

Answer 1

你的y数组看起来像

 ['3']
 ['9']
 ['0']
 ['5']
 ['5']
 ['Triangle']
 ['7']
 ['9']
 ['0']
 ['0']
...

但事实上看起来

[3,9,0,5,5,5,7,9,0,0, ...]