I have a set of houses with categorical and numerical data. Later I will have a new house and my goal will be to find the 20 closest houses. The code is working fine, and the result are not so bad but it is way too long. With a sample of 10 000 houses it takes 6 minutes, using Python 2.7. My actual dataset is about 100 000 houses.

# -*- coding: utf-8 -*-

import csv
import random
import math
import operator
import numpy as np
import pandas as pd, os
from sklearn.preprocessing import OneHotEncoder
from sklearn.feature_extraction import DictVectorizer
from sklearn.preprocessing import StandardScaler
from sklearn.linear_model import LinearRegression
from unidecode import unidecode
import sys
import cProfile
import re


data_pd = pd.read_csv('data.csv')

# I delete rows with NA's (to change later)
data = data.dropna()


# The function I use to deal with categorical data
def one_hot_dataframe(data, cols, replace=False):
    vec = DictVectorizer()
    mkdict = lambda row: dict((col, row[col]) for col in cols)
    vecData = pd.DataFrame(vec.fit_transform(data[cols].apply(mkdict, axis=1)).toarray())
    vecData.columns = vec.get_feature_names()
    vecData.index = data.index
    if replace is True:
        data = data.drop(cols, axis=1)
        data = data.join(vecData)
    return (data, vecData, vec)

# New data set with numerical data only
data_encode, _, _= one_hot_dataframe(data, ['Type', 'Bord_de_mer', 'Bord_de_plan_deau', 'Campagne', 'Centre_ville', 'Complexe_de_vacances', 'Lac', 'Montagne', 'Plage', 'Riviere', 'Village', 'Ville', 'Acces_haut_debit', 'Acces_internet', 'Climatisation', 'Linge_de_maison_fourni', 'Serviettes_de_bain', 'Wifi', 'Terrasse', 'Veranda_Loggia', 'Balcon', 'Jardin', 'location_non_fumeur', 'fumeurs_acceptes', 'animaux_autorises', 'animaux_non_admis', 'acces_handicape', 'Piscine_commune', 'Piscine_privee', 'Piscine_dinterieur', 'Piscine_chauffee', 'Bain_a_remous', 'Sauna'], replace=True)


#convert string to float
data = data.convert_objects(convert_numeric=True)
    
# scaled_col the columns to standardize
scaled_col = ['Capacity', 'BedRooms', 'Latitude', 'Longitude', 'Size', 'Acces_haut_debit=No', 'Acces_haut_debit=Yes', 'Acces_internet=No', 'Acces_internet=Yes', 'Bain_a_remous=No', 'Bain_a_remous=Yes', 'Balcon=No', 'Balcon=Yes', 'Bord_de_mer=No', 'Bord_de_plan_deau=No', 'Bord_de_plan_deau=Yes', 'Campagne=No', 'Campagne=Yes', 'Centre_ville=No', 'Centre_ville=Yes', 'Climatisation=No', 'Climatisation=Yes', 'Complexe_de_vacances=No', 'Complexe_de_vacances=Yes', 'Jardin=No', 'Jardin=Yes', 'Lac=No', 'Lac=Yes', 'Linge_de_maison_fourni=No', 'Linge_de_maison_fourni=Yes', 'Montagne=No', 'Montagne=Yes', 'Piscine_chauffee=No', 'Piscine_chauffee=Yes', 'Piscine_commune=No', 'Piscine_commune=Yes', 'Piscine_dinterieur=No', 'Piscine_privee=No', 'Piscine_privee=Yes', 'Plage=No', 'Plage=Yes', 'Riviere=No', 'Riviere=Yes', 'Sauna=No', 'Sauna=Yes', 'Serviettes_de_bain=No', 'Serviettes_de_bain=Yes', 'Terrasse=No', 'Terrasse=Yes', 'Type=Appartement', 'Type=Chalet', "Type=Chambre d'h\xc3\xb4tes", 'Type=G\xc3\xaete', 'Type=Maison', 'Type=Studio', 'Type=Villa', 'Veranda_Loggia=No', 'Veranda_Loggia=Yes', 'Village=No', 'Village=Yes', 'Ville=No', 'Ville=Yes', 'Wifi=No', 'Wifi=Yes', 'acces_handicape=No', 'acces_handicape=Yes', 'animaux_autorises=No', 'animaux_autorises=Yes', 'animaux_non_admis=No', 'animaux_non_admis=Yes', 'fumeurs_acceptes=No', 'fumeurs_acceptes=Yes', 'location_non_fumeur=No', 'location_non_fumeur=Yes']

# standardization of the dataset   
scaled_features = data.copy()
features = scaled_features[scaled_col]
scaler = StandardScaler().fit(features.values)
features = scaler.transform(features.values)
scaled_features[scaled_col] = features

  
# That's the part where I find weights for the knn algorithm
# I'm using a simple regression and I keep the parameters

#create a new dataframe with the concerned features
weightframe = scaled_features
weightframe = weightframe.drop('DetailUrl', axis = 1)
weightframe = weightframe.drop('index', axis = 1)

X = weightframe.drop('Moyenne', axis = 1)
y = weightframe['Moyenne']

lm = LinearRegression(fit_intercept=False)
lm.fit(X,y)

# df with the features and their weights
weights = pd.DataFrame(zip(X.columns, lm.coef_))

# df with positive values
weights_abs = weights
weights_abs[1] = weights_abs[1].abs()


# Now I can start my knn algorithm
# First I define a distance which is divided by the weights 
def euclideanDistance(instance1, instance2, start, stop):
  distance = 0
  for x in range(start, stop):
    distance += (1/abs(weights.iloc[x-3,1]))*pow((instance1[x] - instance2[x]), 2)
  return math.sqrt(distance)

# Then I find the neighbors
def getNeighbors(trainingSet, testInstance, k):
  distances = trainingSet
  ncol = []
  for x in range(len(trainingSet)):
    dist = euclideanDistance(testInstance, trainingSet.iloc[x,:], 3, len(testInstance))
    ncol.append(dist)
  distances['distance'] = ncol
  distances = distances.sort(['distance'])
  neighbor = distances.head(k)
  return neighbor


# I test my function with the 314th line of the dataset
test = scaled_features.iloc[314,:]
# test_response returns the 20 closest houses
test_response = getNeighbors(scaled_features, test, 20)

#I want to have test_response in its original form (not standardized)
test_response[scaled_col] = scaler.inverse_transform(test_response[scaled_col])

print test_response

I made some quick test and the part which is the longer to execute is the KNN part. The standardization and the regression part are quite quick.

What do you think of my script ? Do you have ideas to increase its performance ? It is definitely too slow.