|  | 
|  | 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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