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NerdTree vim plugin

http://www.catonmat.net/blog/vim-plugins-nerdtree-vim/ I usually use Project plugin for file navigation for my projects, but this NerdTree plugin looks also quite useful. Sometimes, it’s onerous to keep file list in project plugin.

UC Irvine Machine Learning Repository

http://archive.ics.uci.edu/ml/ We currently maintain 187 data sets as a service to the machine learning community. You may view all data sets through our searchable interface. Our old web site is still available, for those who prefer the old format. For a general overview of the Repository, please visit our About page. For information about citing data [...]

Simpson’s paradox

http://en.wikipedia.org/wiki/Simpson’s_paradox A와 B를 비교할때 A의 속성 A[0], A[1]이 각각 B[0], B[1]보다 크다고 하더라도 A[0] + A[1] < B[0] + B[1]일 수 있다는 paradox. 또는 벡터 a1, a2, b1, b2가 있을때 a1의 기울기가 b1보다 크고, a2의 기울기가 b2보다 크다하더라도 a1 + a2 의 기울기가 b1 + b2 의 기울기보다 작을 수 있다.

Empty? Null?

컬렉션 또는 문자열을 반환하는 함수에서 Microsoft는 C#의 경우 빈 컬렉션 혹은 빈 문자열을 권장하고 있다고 하네요. 링크된 글에 설명된 이유는, 1. Null을 반환할 경우 NullReferenceException이 날 경우를 대비해야한다는 reliability 문제. 2. Null도 반환되고 empty 컬렉션/문자열도 반환된다면 이 두가지 모두를 함수를 호출한 곳에서 체크해야하는데 어차피 두경우 모두 처리가 비슷할 것이니 합치는게 낫다는 점. 3. .Net이 그렇게 쓰여져있다는 점입니다. 물론 Null이 꼭 [...]

Sharding

http://www.addsimplicity.com/adding_simplicity_an_engi/2008/08/shard-lessons.html How to set the number of shards is interesting. He recommends 12 as an example because it’s 2*6, 3*4 which means it’s mathematically flexible. He also suggests to think of splitting a shard as tree node split. It would be look more formal if we think of hashing function in the article for sharding [...]

Google Browser Size

http://googlecode.blogspot.com/2009/12/introducing-google-browser-size.html Data on the browser size and the reach rate. Google also provides with a tool that’ll test your website. It’a amazing that this much precious information is shared with the general public.