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Lære Is 4 the Optimal Number of Clusters? | Spectral Clustering
Cluster Analysis in Python
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Kursusindhold

Cluster Analysis in Python

Cluster Analysis in Python

1. K-Means Algorithm
2. K-Medoids Algorithm
3. Hierarchical Clustering
4. Spectral Clustering

book
Is 4 the Optimal Number of Clusters?

The last chart (displayed below) left the question about an optimal number of clusters unanswered. Seems like 4 is the 'local maximum', but the value 5 is not significantly lower than 4. We need to consider both cases.

Let's watch the scatter plot of average January vs July temperatures in the case of 4 clusters.

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# Import the libraries import pandas as pd import matplotlib.pyplot as plt import seaborn as sns from sklearn.cluster import SpectralClustering # Read the data data = pd.read_csv('https://codefinity-content-media.s3.eu-west-1.amazonaws.com/138ab9ad-aa37-4310-873f-0f62abafb038/Cities+weather.csv', index_col = 0) # Create the model model = SpectralClustering(n_clusters = 4, affinity = 'nearest_neighbors') # Fit the data and predict the labels data['prediction'] = model.fit_predict(data.iloc[:,2:14]) # Visualize the results sns.scatterplot(x = 'Jan', y = 'Jul', hue = 'prediction', data = data) plt.show()
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The clustering seems logical, it splits the cities into different disjoint groups. But what if we build the same chart but for 5 clusters? That will be your task!

Opgave

Swipe to start coding

Table
  1. Import SpectralClustering function from sklearn.cluster.
  2. Create a SpectralClustering model with 5 clusters using the 'nearest_neighbors' affinity.
  3. Fit the 3-14 columns of data to the model and predict the labels. Save the result within the 'prediction' column of data.
  4. Build the seaborn scatter plot with average January (column 'Jan') vs July (column 'Jul') temperatures for each cluster (column 'prediction').

Løsning

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Sektion 4. Kapitel 5
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book
Is 4 the Optimal Number of Clusters?

The last chart (displayed below) left the question about an optimal number of clusters unanswered. Seems like 4 is the 'local maximum', but the value 5 is not significantly lower than 4. We need to consider both cases.

Let's watch the scatter plot of average January vs July temperatures in the case of 4 clusters.

123456789101112131415161718
# Import the libraries import pandas as pd import matplotlib.pyplot as plt import seaborn as sns from sklearn.cluster import SpectralClustering # Read the data data = pd.read_csv('https://codefinity-content-media.s3.eu-west-1.amazonaws.com/138ab9ad-aa37-4310-873f-0f62abafb038/Cities+weather.csv', index_col = 0) # Create the model model = SpectralClustering(n_clusters = 4, affinity = 'nearest_neighbors') # Fit the data and predict the labels data['prediction'] = model.fit_predict(data.iloc[:,2:14]) # Visualize the results sns.scatterplot(x = 'Jan', y = 'Jul', hue = 'prediction', data = data) plt.show()
copy

The clustering seems logical, it splits the cities into different disjoint groups. But what if we build the same chart but for 5 clusters? That will be your task!

Opgave

Swipe to start coding

Table
  1. Import SpectralClustering function from sklearn.cluster.
  2. Create a SpectralClustering model with 5 clusters using the 'nearest_neighbors' affinity.
  3. Fit the 3-14 columns of data to the model and predict the labels. Save the result within the 'prediction' column of data.
  4. Build the seaborn scatter plot with average January (column 'Jan') vs July (column 'Jul') temperatures for each cluster (column 'prediction').

Løsning

Switch to desktopSkift til skrivebord for at øve i den virkelige verdenFortsæt der, hvor du er, med en af nedenstående muligheder
Var alt klart?

Hvordan kan vi forbedre det?

Tak for dine kommentarer!

Sektion 4. Kapitel 5
Switch to desktopSkift til skrivebord for at øve i den virkelige verdenFortsæt der, hvor du er, med en af nedenstående muligheder
Vi beklager, at noget gik galt. Hvad skete der?
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