CODEWITHSUNDEEP
pythonmachine-learningscikit-learnk-means
Greg Sullivan
Greg Sullivan

Reputation: 183

how to graph centroids with KMeans

I am working with a data set and trying to learn how to use cluster analysis and KMeans. I started out with a scatter plot graphing 2 attributes, and when I add a third attribute, and try and graph a another centroid I get an error. The code I am running is the following:

import numpy as np ##Import necassary packages
import pandas as pd
import matplotlib.pyplot as plt
from matplotlib import style
style.use("ggplot")
from pandas.plotting import scatter_matrix
from sklearn.preprocessing import *
from sklearn.cluster import MiniBatchKMeans 


url2="http://archive.ics.uci.edu/ml/machine-learning-databases/adult/adult.data" #Reading in Data from a freely and easily available source on the internet
Adult = pd.read_csv(url2, header=None, skipinitialspace=True) #Decoding data by removing extra spaces in cplumns with skipinitialspace=True
##Assigning reasonable column names to the dataframe
Adult.columns = ["age","workclass","fnlwgt","education","educationnum","maritalstatus","occupation",  
                 "relationship","race","sex","capitalgain","capitalloss","hoursperweek","nativecountry",
                 "less50kmoreeq50kn"]
Adult.loc[:, "White"] = (Adult.loc[:, "race"] == "White").astype(int)

X = pd.DataFrame()
X.loc[:,0] = Adult.loc[:,'age']
X.loc[:,1] = Adult.loc[:,'hoursperweek']
X.loc[:,2] = Adult.loc[:, "White"]

kmeans = MiniBatchKMeans(n_clusters = 3)
kmeans.fit(X)

centroids = kmeans.cluster_centers_
labels = kmeans.labels_

print(centroids)
print(labels)

colors = ["green","red","blue"]

plt.scatter(X.iloc[:,0], X.iloc[:,1], X.iloc[:,2], c=np.array(colors)[labels], alpha=.1)

plt.scatter(centroids[:, 0], centroids[:, 1],  marker = "x", s=150, 
    linewidths = 5, zorder = 10, c=['green', 'red','blue'])
plt.show()

Running the code works however it does not seem correct as there are only 2 centroids being 'called' but 3 centroids are still plotted. when I change the centroid scatter plot to:

plt.scatter(centroids[:, 0], centroids[:, 1], centroids[:, 2] marker = "x", s=150, 
        linewidths = 5, zorder = 10, c=['green', 'red','blue'])

I get a TypeError: scatter() got multiple values for argument 's'. Is the original incorrect code and will it cause problems in future projects? if so how should I change the code to where I do not receive an error? Thanks in advance

Upvotes: 3

Views: 12811

Answers (1)

Rajith Thennakoon
Rajith Thennakoon

Reputation: 4130

Issue is if you pass argument values without keys,scatter function expect 3rd argument to be s.In your case third argument is centroid and again you passing s as a keyword argument.so it got multiple values to s.what you need is something like this.

1) Assign the columns of centroids: centroids_x, centroids_y

centroids_x = centroids[:,0]
centroids_y = centroids[:,1]

2) Make a scatter plot of centroids_x and centroids_y

plt.scatter(centroids_x,centroids_y,marker = "x", s=150,linewidths = 5, zorder = 10, c=['green', 'red','blue'])

Upvotes: 7

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