| 
 | 1 | +import random  | 
 | 2 | + | 
 | 3 | +import matplotlib.pyplot as plt  | 
 | 4 | +import numpy as np  | 
1 | 5 | import pandas as pd  | 
2 |  | -data = pd.read_csv('https://s3.amazonaws.com/demo-datasets/wine.csv')  | 
 | 6 | +import sklearn.decomposition  | 
 | 7 | +from matplotlib.colors import ListedColormap  | 
 | 8 | +#  More accuracy  | 
 | 9 | +from sklearn.neighbors import KNeighborsClassifier  | 
3 | 10 | 
 
  | 
4 | 11 | 
 
  | 
 | 12 | +def accuracy(predictions, outcomes):  | 
 | 13 | +    # Enter your code here!  | 
 | 14 | +    occur = 0  | 
 | 15 | +    v = np.array(predictions) == np.array(outcomes)  | 
 | 16 | +    occur = np.sum(v)  | 
 | 17 | +    return occur  | 
5 | 18 | 
 
  | 
6 |  | -df2 = data.drop('color', axis=1) # color is redundant  | 
7 | 19 | 
 
  | 
 | 20 | +data = pd.read_csv('https://s3.amazonaws.com/demo-datasets/wine.csv')  | 
8 | 21 | 
 
  | 
9 |  | -import numpy as np  | 
 | 22 | +df2 = data.drop('color', axis=1)  # color is redundant  | 
10 | 23 | 
 
  | 
 | 24 | +numeric_data = df2.values  | 
11 | 25 | 
 
  | 
 | 26 | +numeric_data = (numeric_data - np.mean(numeric_data)) / (np.std(numeric_data))  | 
12 | 27 | 
 
  | 
13 |  | -numeric_data =  (numeric_data - np.mean(numeric_data))/(np.std(numeric_data))    | 
14 | 28 | 
 
  | 
15 |  | -import sklearn.decomposition  | 
16 | 29 | pca = sklearn.decomposition.PCA(n_components=2)  | 
17 | 30 | principal_components = pca.fit(numeric_data).transform(numeric_data)  | 
18 | 31 | 
 
  | 
19 |  | - | 
20 |  | - | 
21 |  | - | 
22 |  | - | 
23 |  | -import matplotlib.pyplot as plt  | 
24 |  | -from matplotlib.colors import ListedColormap  | 
25 |  | -from matplotlib.backends.backend_pdf import PdfPages  | 
26 | 32 | observation_colormap = ListedColormap(['red', 'blue'])  | 
27 |  | -x = principal_components[:,0]  | 
28 |  | -y = principal_components[:,1]  | 
 | 33 | +x = principal_components[:, 0]  | 
 | 34 | +y = principal_components[:, 1]  | 
29 | 35 | 
 
  | 
30 | 36 | plt.title("Principal Components of Wine")  | 
31 |  | -plt.scatter(x, y, alpha = 0.2,  | 
32 |  | -    c = data['high_quality'], cmap = observation_colormap, edgecolors = 'none')  | 
33 |  | -plt.xlim(-8, 8); plt.ylim(-8, 8)  | 
34 |  | -plt.xlabel("Principal Component 1"); plt.ylabel("Principal Component 2")  | 
 | 37 | +plt.scatter(x, y, alpha=0.2,  | 
 | 38 | +            c=data['high_quality'], cmap=observation_colormap,  | 
 | 39 | +            edgecolors='none')  | 
 | 40 | +plt.xlim(-8, 8)  | 
 | 41 | +plt.ylim(-8, 8)  | 
 | 42 | +plt.xlabel("Principal Component 1")  | 
 | 43 | +plt.ylabel("Principal Component 2")  | 
35 | 44 | plt.show()  | 
36 | 45 | 
 
  | 
 | 46 | +x = np.array([1, 2, 3])  | 
 | 47 | +y = np.array([1, 2, 4])  | 
37 | 48 | 
 
  | 
 | 49 | +print(accuracy(x, y))  | 
38 | 50 | 
 
  | 
 | 51 | +print(accuracy([], data["high_quality"]))  | 
39 | 52 | 
 
  | 
40 |  | - | 
41 |  | -def accuracy(predictions, outcomes):  | 
42 |  | -    # Enter your code here!  | 
43 |  | -    occur =0  | 
44 |  | -    for i in range(len(predictions)):  | 
45 |  | -        if(predictions[i] == outcomes[i]):  | 
46 |  | -            occur += 1  | 
47 |  | -    return occur  | 
48 |  | -      | 
49 |  | - | 
50 |  | -x = np.array([1,2,3])  | 
51 |  | -y = np.array([1,2,4])  | 
52 |  | - | 
53 |  | -print (accuracy(x,y))  | 
54 |  | - | 
55 |  | - | 
56 |  | -print(accuracy(0,data["high_quality"]))  | 
57 |  | - | 
58 |  | - | 
59 |  | -##############################   More accuracy  | 
60 |  | -from sklearn.neighbors import KNeighborsClassifier  | 
61 |  | -knn = KNeighborsClassifier(n_neighbors = 5)  | 
 | 53 | +knn = KNeighborsClassifier(n_neighbors=5)  | 
62 | 54 | knn.fit(numeric_data, data['high_quality'])  | 
63 | 55 | # Enter your code here!  | 
64 | 56 | 
 
  | 
65 | 57 | library_predictions = knn.predict(numeric_data)  | 
66 | 58 | 
 
  | 
67 |  | -print(accuracy(library_predictions,data['high_quality']))  | 
 | 59 | +print(accuracy(library_predictions, data['high_quality']))  | 
68 | 60 | 
 
  | 
69 |  | -################  | 
70 | 61 | n_rows = data.shape[0]  | 
71 | 62 | 
 
  | 
 | 63 | +print()  | 
72 | 64 | random.seed(123)  | 
73 | 65 | selection = random.sample(range(n_rows), 10)  | 
74 | 66 | 
 
  | 
75 |  | - | 
76 | 67 | predictors = np.array(numeric_data)  | 
77 | 68 | training_indices = [i for i in range(len(predictors)) if i not in selection]  | 
78 | 69 | outcomes = np.array(data["high_quality"])  | 
79 | 70 | 
 
  | 
80 |  | -my_predictions = [knn_predict(p, predictors[training_indices,:], outcomes, k=5) for p in predictors[selection]]  | 
81 |  | -percentage = accuracy(my_predictions,data.high_quality[selection])  | 
 | 71 | +my_predictions = [  | 
 | 72 | +    knn.predict(predictors[training_indices, :]) for p in  | 
 | 73 | +    predictors[selection]]  | 
 | 74 | +percentage = accuracy(my_predictions, outcomes)  | 
82 | 75 | 
 
  | 
83 | 76 | print(percentage)  | 
84 |  | - | 
85 |  | - | 
86 |  | - | 
87 |  | - | 
88 |  | - | 
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