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andbis committed Jul 13, 2019
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import numpy as np
import math
from collections import Counter
import pandas as pd

#min max normalisation
def min_max(differences, range=(0,1.0)):
#min max
max_val = max(differences)
min_val = min(differences)

return np.multiply(np.subtract(range[1], range[0]), np.divide( np.subtract(differences, min_val), np.subtract(max_val, min_val)))

#zero mean score normalisation
def normalizer(data):
feature_means = [[] for a in range(data.shape[1])]
feature_sigma = [[] for a in range(data.shape[1])]
for i, mean in enumerate(feature_means):
feature_means[i] = data[:,i].mean()
feature_sigma[i] = data[:,i].std()

normalized = np.empty(data.shape)

for i, el in np.ndenumerate(data):
normalized[i] = (el - feature_means[i[1]]) / feature_sigma[i[1]]

return normalized

#Apriori algorithm
def apriori(D, min_sup=0.2, delimiter=';'):
big_L = []
number_of_t = len(D)
#first set of frequent 1 itemsets is found by scanning D
k = 1
f = 0
while f != 1:
# print('iteration',k)
if k == 1:
c1 = {}
for t in D:
if delimiter == ';':
splitted = t.split(delimiter)
transaction = set(splitted)
transaction = set(t)

for item in transaction:
if item in c1:
c1[item] += 1
c1[item] = 1

l1 = {}
for keys in c1.items():
if keys[1]/number_of_t >= min_sup:
l1[keys[0]] = keys[1]
k += 1


#generating next C candidates
C = {}
if k == 2:
L = l1
L = new_L

c_keys = list(L.keys())
for idx, i in enumerate(c_keys):
for indel, j in enumerate(c_keys[idx+1:]):
idk = j.split(',')
if len(idk) == 1:
C[i + ',' + j] = 0
for el in idk:
if el in i:
C[i+','+el] = 0

#remove Duplicates
remove = []
keys2remove = []
deleted = []
for idx, keys in enumerate(C.keys()):
splitted_keys = sorted(keys.split(','))
for indel, keys_2 in enumerate(C.keys()):
if indel > idx:
compares = sorted(keys_2.split(','))
if splitted_keys == compares and idx != indel:
if [idx, indel] in remove or [indel, idx] in remove: pass
elif indel in deleted: pass
remove.append([idx, indel])

#deleting duplicates from C dictionary
if len(keys2remove) != 0:
for keys in keys2remove:
del C[keys]

#Scan D for support
for t in D:
if delimiter == ';':
splitted = t.split(delimiter)
transaction = set(splitted)
transaction = set(t)

for keys in C.keys():
sub_count = 0
for key in keys.split(','):
if key in transaction: sub_count += 1
if sub_count == len(keys.split(',')):
C[keys] += 1

#compare candidate support with min_sup
new_L = {}
for keys in C.items():
if keys[1]/number_of_t >= min_sup:

new_L[keys[0]] = keys[1]

if len(new_L) != 0: #appending L to big_L if L != empty

f = 1
k += 1

return big_L

#Euclidean distance used both in K-nn and K-means to calculate the distance between two vectors
def euclidean_distance(v1, v2):
#returns the euclidean distance from vector one (p) to vector two (q)
summed = 0
for p, q in zip(v1, v2):
summed += (p - q) ** 2
return np.sqrt(summed)

#K_NN functions:
#the below two functions and orderedlisttuple class is used to hold nearest neighbours
def get (LIST, index):
return LIST[index]

def get_value(el):
return el[1]

class OrderedListTuple:
#Create a data strutcture with two elements.
#A sorted list
def __init__(self, max_size):
self.content = []
self.max_size = max_size

def find_pos (self, element):
index = 0
while (index <= len(self.content)-1) and get_value(get(self.content, index)) < get_value(element):
index += 1
return index

def insert_element (self, element):
pos = self.find_pos (element)
self.content.insert (pos, element)
if len(self.content) > self.max_size:

def k_nen(k, train_x, train_y, test_x):
#returns list of predicted labels for data
if k % 2 != 1:
raise ValueError('Please enter uneven k')
#initialising list to hold predicted labels
results = []
#iterating over data, using index and element(v1)
for idx, v1 in enumerate(test_x):
#generating list of tuple to hold K nearest neighbors
nearest_neighbours = OrderedListTuple(k)
#iterating over data to calculate distance
for i, v2 in enumerate(train_x):
#calculating the euclidean distance
c_dist = euclidean_distance(v1, v2)
#adding index and distance to orderedlisttuple
nearest_neighbours.insert_element((i, c_dist))
#Initialising dict to hold count of labels in k-nn
nearest = {}
#iterating over k nearest neigbors to predict label
for l in nearest_neighbours.content:
c_label = train_y[l[0]]
if c_label in nearest:
nearest[c_label] += 1
nearest[c_label] = 1
#appending most frequent label to results list
results.append(max(nearest, key=nearest.get))
return results

#Compares two list of labels and returns the accuracy
def accuracy(labels_1, labels_2):
if len(labels_1) != len(labels_2):
raise ValueError('Labels length do not match')
return round(len(np.where(np.array(labels_1)== np.array(labels_2))[0])/len(labels_1),4)

#Used to split data set in k parts in cross validation
def new_split(data, idx, k=5):
size_of_sets = data.shape[0] / k
if size_of_sets % 2 != 0:
raise ValueError('This splitter only works for splitting equal sized sets')
test = data[int(size_of_sets*idx):int((size_of_sets*idx)+size_of_sets)]
if idx == 0:
train = data[int(size_of_sets):]

if idx == k:
train = data[:-int(size_of_sets)]
remainder = np.delete(data, [range(int(idx*size_of_sets), int((size_of_sets*idx)+size_of_sets))], axis=0)
train = remainder
return test, train

#Used to find best_k and sort ascending
def best_k(results, kays):
classification_error = []
for k in kays:
c_k = [a[-1] for a in results if a[0] == k]
classification_error.append([k, sum(c_k) / len(c_k)])
average = np.array(classification_error)
return average[average[:,1].argsort()]

#K_Means functions:
#Iterating through data and assigning class by calculating euclidean distance to cluster centers
#the closest assigns the same label to data point
def assignment(centroids, data):
a = data
for i, a_vector in enumerate(a):
cluster = [int, math.inf]
for idx, centroid_vector in enumerate(centroids):
c_dist = euclidean_distance(a_vector, centroid_vector)
if c_dist < cluster[1]:
cluster = [idx, c_dist]
a[i,-1] = int(cluster[0])
return a

#calculates the mean cluster and returns the new centroids/cluster centers
def mean_cluster(centroids, data):
k = centroids.shape[0]
dimensions = centroids.shape[1]
new_centroids = np.zeros(centroids.shape)

for i in range(k): #for every cluster
cluster = np.array([vector for vector in data if int(vector[-1]) == int(i)])
if cluster.shape[0] != 0:
for idx in range(dimensions):

new_centroids[i, idx] = np.sum(cluster[:,idx])/len(cluster)

return new_centroids
#Adds extra column to hold label
def add_label_col(data):
#Creating a to hold numpy and cluster assignment
a = np.zeros((data.shape[0], data.shape[1]+1))
a[:,:-1] = data
return a

#Creates c number of centroids in the range of the data
def centroid_maker(c, data):
centroids = np.empty((c, data.shape[1]))
for i, j in np.ndenumerate(centroids):
centroids[i] = np.random.uniform(data[:,i[1]].min(), data[:,i[1]].max())
return centroids

#Used to calculate the purity of the clusters NOT PRECISION
def purity(labeled_data, labels):
#assigns most frequent true class as true class for cluster
#compares with number of points in cluster
if len(labeled_data.shape) == 1:
classes = set(labeled_data)
classes = set(labeled_data[:,-1])
purity = []
for i in classes:
c_class = []
for idx, j in enumerate(labeled_data):
if int(i) == int(j[-1]):
c_class.append([idx, j[-1]])

true_labels = []
for el in c_class:

most = Counter(true_labels)
label_for_cluster = most.most_common(1)[0][0]

countlabel = 0
for b in true_labels:
if int(b) == int(label_for_cluster):
countlabel += 1

purity.append(countlabel / len(true_labels))
most = 0

return sum(purity) / len(purity)

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Contact me to get the data

Algorithms used:
Apriori - frequent pattern mining
K-NN - nearest neighbour
K-Means - clustering, unsupervised

Included in this folder should be the following files: - Script file that should be run - Python library file containing all functions used
Data Mining - Spring 2018.csv - data - included because it's only 66KB

Following has been uploaded separately: run.pdf - Report of experiments

IMPORTANT: It's assumed that file 'Data Mining - Spring 2018.csv' is in the same directory as and, otherwise data won't be found.

Program has been developed and tested on following setup:
OSX: 10.13.3
Python: 3.6.3 - Anaconda build
Packages used:

In addition to what the script file will print, it will also save two figures in the directory.

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