netflix 推荐算法学习1(转)

http://www.csie.ntu.edu.tw/~r95007/thesis/svdnetflix/report/report.pdf
http://eecs.wsu.edu/~vjakkula/MLProject.pdf
http://michielvanwezel.com/papers/kagie_vdloos_vwezelV2.pdf
http://cseweb.ucsd.edu/users/elkan/KddNetflixWorkshop.pdf
http://www.cs.uic.edu/~liub/KDD-cup-2007/proceedings/The-Netflix-Prize-Bennett.pdf

准备数据集
1shell 将所有测试数据集文件合并为一个文件
#!/bin/bash
for x in netflix/training_set/mv_*.txt ;
 do cat $x >> ratings.txt ;
done &

http://www.netflixprize.com/community/viewtopic.php?id=87
需要下载path模块
#!/usr/bin/env python

import sys
import csv
from path import path

NULL = '\N'

class Dialect(csv.excel):
    delimiter = '\t'
    lineterminator = '\n'
    doublequote = False
    escapechar = None
    quoting = csv.QUOTE_MINIMAL

def csvDump(iter_rows_func, basename, dir='.', csvdir='csv', dialect=Dialect):
    dir,csvdir = path(dir),path(csvdir)
    if not csvdir.exists():
        csvdir.mkdir()
    inpath = dir/basename
    outfile = csvdir/inpath.namebase + '.csv'
    if not outfile.exists():
        write = csv.writer(open(outfile, 'wb'), dialect).writerow
        print >> sys.stderr, 'Writing %s ...' % outfile
        for row in iter_rows_func(inpath):
            write(row)

def iterMovieRows(path):
    for line in open(path):
        id,year,title = line.rstrip().split(',',2)
        year = year!='NULL' and int(year) or NULL
        yield (int(id), year, title)

def iterTrainingSetRows(dir):
    for path in dir.walkfiles():
        iterlines = (line.strip() for line in open(path))
        movie_id = int(iterlines.next()[:-1])
        for line in iterlines:
            user_id,rating,date = line.split(',',2)
            yield (movie_id, int(user_id), date, float(rating))

def iterProbeSetRows(path):
    for line in (line.strip() for line in open(path)):
        try:
            user_id = int(line)
        except ValueError:
            movie_id = int(line[:-1])
        else:
            yield (movie_id,user_id)

def iterQualifyingSetRows(path):
    for line in (line.strip() for line in open(path)):
        try:
            user_id,date = line.split(',')
        except ValueError:
            movie_id = int(line[:-1])
        else: