test_k-means.py

# Blog: http://blog.csdn.net/fengbingchun/article/details/79305768
# reference: https://mubaris.com/2017/10/01/kmeans-clustering-in-python/

from copy import deepcopy
import numpy as np
import pandas as pd
from matplotlib import pyplot as plt
import os

os_name = os.name
if os_name == "posix": # linux
	print("python running on linux")
else: # nt: windows
	print("python running on windows")

#plt.rcParams['figure.figsize'] = (16, 9)
#plt.style.use('ggplot')

# Importing the dataset
if os_name == "posix":
	data = pd.read_csv('../../../data/database/xclara.csv')
else:
	data = pd.read_csv('../../data/database/xclara.csv')
#print(data.shape)
data.head()

# Getting the values and plotting it
f1 = data['V1'].values
f2 = data['V2'].values
X = np.array(list(zip(f1, f2)))
#plt.scatter(f1, f2, c='black', s=7)

# Euclidean Distance Caculator
def dist(a, b, ax=1):
    return np.linalg.norm(a - b, axis=ax)

# Number of clusters
k = 3
# X coordinates of random centroids
C_x = np.random.randint(0, np.max(X)-20, size=k)
# Y coordinates of random centroids
C_y = np.random.randint(0, np.max(X)-20, size=k)
C = np.array(list(zip(C_x, C_y)), dtype=np.float32)
#print(C)

# Plotting along with the Centroids
#plt.scatter(f1, f2, c='#050505', s=7)
#plt.scatter(C_x, C_y, marker='*', s=200, c='g')

# To store the value of centroids when it updates
C_old = np.zeros(C.shape)
# Cluster Lables(0, 1, 2)
clusters = np.zeros(len(X))
# Error func. - Distance between new centroids and old centroids
error = dist(C, C_old, None)
# Loop will run till the error becomes zero
while error != 0:
    # Assigning each value to its closest cluster
    for i in range(len(X)):
        distances = dist(X[i], C)
        cluster = np.argmin(distances)
        clusters[i] = cluster
    # Storing the old centroid values
    C_old = deepcopy(C)
    # Finding the new centroids by taking the average value
    for i in range(k):
        points = [X[j] for j in range(len(X)) if clusters[j] == i]
        C[i] = np.mean(points, axis=0)
    error = dist(C, C_old, None)

colors = ['r', 'g', 'b', 'y', 'c', 'm']
fig, ax = plt.subplots()
for i in range(k):
        points = np.array([X[j] for j in range(len(X)) if clusters[j] == i])
        ax.scatter(points[:, 0], points[:, 1], s=7, c=colors[i])
ax.scatter(C[:, 0], C[:, 1], marker='*', s=200, c='#050505')

plt.show()