import math
import sys
from texttable import Texttable
def calcCosDistSpe(user1,user2):
avg_x=0.0
avg_y=0.0
for key in user1:
avg_x+=key[1]
avg_x=avg_x/len(user1)
for key in user2:
avg_y+=key[1]
avg_y=avg_y/len(user2)
u1_u2=0.0
for key1 in user1:
for key2 in user2:
if key1[1] > avg_x and key2[1]>avg_y and key1[0]==key2[0]:
u1_u2+=1
u1u2=len(user1)*len(user2)*1.0
sx_sy=u1_u2/math.sqrt(u1u2)
return sx_sy
def calcCosDist(user1,user2):
sum_x=0.0
sum_y=0.0
sum_xy=0.0
for key1 in user1:
for key2 in user2:
if key1[0]==key2[0] :
sum_xy+=key1[1]*key2[1]
sum_y+=key2[1]*key2[1]
sum_x+=key1[1]*key1[1]
if sum_xy == 0.0 :
return 0
sx_sy=math.sqrt(sum_x*sum_y)
return sum_xy/sx_sy
def calcSimlaryCosDist(user1,user2):
sum_x=0.0
sum_y=0.0
sum_xy=0.0
avg_x=0.0
avg_y=0.0
for key in user1:
avg_x+=key[1]
avg_x=avg_x/len(user1)
for key in user2:
avg_y+=key[1]
avg_y=avg_y/len(user2)
for key1 in user1:
for key2 in user2:
if key1[0]==key2[0] :
sum_xy+=(key1[1]-avg_x)*(key2[1]-avg_y)
sum_y+=(key2[1]-avg_y)*(key2[1]-avg_y)
sum_x+=(key1[1]-avg_x)*(key1[1]-avg_x)
if sum_xy == 0.0 :
return 0
sx_sy=math.sqrt(sum_x*sum_y)
return sum_xy/sx_sy
def readFile(file_name):
contents_lines=[]
f=open(file_name,"r")
contents_lines=f.readlines()
f.close()
return contents_lines
def getRatingInformation(ratings):
rates=[]
for line in ratings:
rate=line.split("\t")
rates.append([int(rate[0]),int(rate[1]),int(rate[2])])
return rates
def createUserRankDic(rates):
user_rate_dic={}
item_to_user={}
for i in rates:
user_rank=(i[1],i[2])
if i[0] in user_rate_dic:
user_rate_dic[i[0]].append(user_rank)
else:
user_rate_dic[i[0]]=[user_rank]
if i[1] in item_to_user:
item_to_user[i[1]].append(i[0])
else:
item_to_user[i[1]]=[i[0]]
return user_rate_dic,item_to_user
def calcNearestNeighbor(userid,users_dic,item_dic):
neighbors=[]
for item in users_dic[userid]:
for neighbor in item_dic[item[0]]:
if neighbor != userid and neighbor not in neighbors:
neighbors.append(neighbor)
neighbors_dist=[]
for neighbor in neighbors:
dist=calcSimlaryCosDist(users_dic[userid],users_dic[neighbor])
neighbors_dist.append([dist,neighbor])
neighbors_dist.sort(reverse=True)
return neighbors_dist
def recommendByUserFC(file_name,userid,k=5):
test_contents=readFile(file_name)
test_rates=getRatingInformation(test_contents)
test_dic,test_item_to_user=createUserRankDic(test_rates)
neighbors=calcNearestNeighbor(userid,test_dic,test_item_to_user)[:k]
recommend_dic={}
for neighbor in neighbors:
neighbor_user_id=neighbor[1]
movies=test_dic[neighbor_user_id]
for movie in movies:
if movie[0] not in recommend_dic:
recommend_dic[movie[0]]=neighbor[0]
else:
recommend_dic[movie[0]]+=neighbor[0]
recommend_list=[]
for key in recommend_dic:
recommend_list.append([recommend_dic[key],key])
recommend_list.sort(reverse=True)
user_movies = [ i[0] for i in test_dic[userid]]
return [i[1] for i in recommend_list],user_movies,test_item_to_user,neighbors
def getMoviesList(file_name):
movies_contents=readFile(file_name)
movies_info={}
for movie in movies_contents:
movie_info=movie.split("|")
movies_info[int(movie_info[0])]=movie_info[1:]
return movies_info
if __name__ == '__main__':
reload(sys)
sys.setdefaultencoding('utf-8')
movies=getMoviesList("/Users/wuyinghao/Downloads/ml-100k/u.item")
recommend_list,user_movie,items_movie,neighbors=recommendByUserFC("/Users/wuyinghao/Downloads/ml-100k/u.data",179,80)
neighbors_id=[ i[1] for i in neighbors]
table = Texttable()
table.set_deco(Texttable.HEADER)
table.set_cols_dtype(['t',
't',
't'])
table.set_cols_align(["l", "l", "l"])
rows=[]
rows.append([u"movie name",u"release", u"from userid"])
for movie_id in recommend_list[:20]:
from_user=[]
for user_id in items_movie[movie_id]:
if user_id in neighbors_id:
from_user.append(user_id)
rows.append([movies[movie_id][0],movies[movie_id][1],""])
table.add_rows(rows)
print table.draw()
结果
movie name release
=======================================================
Contact (1997) 11-Jul-1997
Scream (1996) 20-Dec-1996
Liar Liar (1997) 21-Mar-1997
Saint, The (1997) 14-Mar-1997
English Patient, The (1996) 15-Nov-1996
Titanic (1997) 01-Jan-1997
Air Force One (1997) 01-Jan-1997
Star Wars (1977) 01-Jan-1977
Conspiracy Theory (1997) 08-Aug-1997
Toy Story (1995) 01-Jan-1995
Fargo (1996) 14-Feb-1997
