Comments on: O’Reilly Make me an Offer!

By: thecapacity : What if stocks were movies?

thecapacity : What if stocks were movies? — Mon, 07 Jul 2008 20:40:17 +0000

[...] you’ve seen from my previous posts, I’ve been playing with python, couchdb and been working my way through the “Programming Collective Intelligence” book. However, what I haven’t been [...]

By: thecapacity : My how long it’s been…

thecapacity : My how long it’s been… — Fri, 30 May 2008 17:20:51 +0000

[...] weeks! Wow, yes it’s really been that long since I started reading Programming Collective Intelligence and last posted [...]

By: jay

jay — Tue, 22 Apr 2008 02:26:17 +0000

P17 when doing the “getRecommendations()” call with “similarity=sim_distance” you will get slightly different values for the 3 movies then what’s listed (because of the previous function errors) but it’s a minimal error.

By: jay

jay — Tue, 22 Apr 2008 02:02:07 +0000

p14 -
Not a big but in “Ranking the Critics…” in the code there’s no need to reverse the full list;
Here’s the code ‘as is’;

scores.sort()
scores.reverse()
return scores[0:n]

This could simply be;
scores.sort()
return scores[-1:-(n+1):-1]

The syntax’s a little strange but it would save you reversing a big list.

I think you could also probably sort the list then just slice the parts you need off and then just reverse that new list.

By: jay

jay — Sun, 20 Apr 2008 17:22:34 +0000

As I mentioned I’ve found it instructive to hand type in the python code for this book. Also I didn’t really feel like signing up for Safari (O’Reilly’s online book library) but today I discovered that you can get a zip file of all the code!

Thanks to this post
http://blog.kiwitobes.com/?p=44

Here’s the direct link
http://kiwitobes.com/PCI_Code.zip

By: jay

jay — Sat, 19 Apr 2008 23:06:16 +0000

p14 (3rd paragraph) - “sim_vecror” should be “sim_distance”.

More interesting, I finished the two movie recommendations exercises (but not done “Top Matches” yet) and I was really surprised at the variability of the results given by the two methods (Euclidean vs. Pearson );

Jack Matthews and Mick LaSalle => D(0.286) P(0.211)
Jack Matthews and Claudia Puig => D(0.320) P(0.029)
Jack Matthews and Lisa Rose => D(0.341) P(0.747)
Jack Matthews and Toby => D(0.267) P(0.663)
Jack Matthews and Gene Seymour => D(0.667) P(0.964)
Jack Matthews and Michael Phillips => D(0.320) P(0.135)

Mick LaSalle and Jack Matthews => D(0.286) P(0.211)
Mick LaSalle and Claudia Puig => D(0.315) P(0.567)
Mick LaSalle and Lisa Rose => D(0.414) P(0.594)
Mick LaSalle and Toby => D(0.400) P(0.924)
Mick LaSalle and Gene Seymour => D(0.278) P(0.412)
Mick LaSalle and Michael Phillips => D(0.387) P(-0.258)

Claudia Puig and Jack Matthews => D(0.320) P(0.029)
Claudia Puig and Mick LaSalle => D(0.315) P(0.567)
Claudia Puig and Lisa Rose => D(0.387) P(0.567)
Claudia Puig and Toby => D(0.357) P(0.893)
Claudia Puig and Gene Seymour => D(0.282) P(0.315)
Claudia Puig and Michael Phillips => D(0.536) P(1.000)

Lisa Rose and Jack Matthews => D(0.341) P(0.747)
Lisa Rose and Mick LaSalle => D(0.414) P(0.594)
Lisa Rose and Claudia Puig => D(0.387) P(0.567)
Lisa Rose and Toby => D(0.348) P(0.991)
Lisa Rose and Gene Seymour => D(0.294) P(0.396)
Lisa Rose and Michael Phillips => D(0.472) P(0.405)

Toby and Jack Matthews => D(0.267) P(0.663)
Toby and Mick LaSalle => D(0.400) P(0.924)
Toby and Claudia Puig => D(0.357) P(0.893)
Toby and Lisa Rose => D(0.348) P(0.991)
Toby and Gene Seymour => D(0.258) P(0.381)
Toby and Michael Phillips => D(0.387) P(-1.000)

Gene Seymour and Jack Matthews => D(0.667) P(0.964)
Gene Seymour and Mick LaSalle => D(0.278) P(0.412)
Gene Seymour and Claudia Puig => D(0.282) P(0.315)
Gene Seymour and Lisa Rose => D(0.294) P(0.396)
Gene Seymour and Toby => D(0.258) P(0.381)
Gene Seymour and Michael Phillips => D(0.341) P(0.205)

Michael Phillips and Jack Matthews => D(0.320) P(0.135)
Michael Phillips and Mick LaSalle => D(0.387) P(-0.258)
Michael Phillips and Claudia Puig => D(0.536) P(1.000)
Michael Phillips and Lisa Rose => D(0.472) P(0.405)
Michael Phillips and Toby => D(0.387) P(-1.000)
Michael Phillips and Gene Seymour => D(0.341) P(0.205)

I assume some of it could be related to the relatively few data points (sometimes critics only share 2 of 5 movies.

Any other ideas?