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Monday, February 6, 2012

Using apply() to create a unique id

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Suppose you have a data set with two identifiers. For example, maybe you're studying the relationships among firms in an industry and y...
6 comments:
Friday, July 29, 2011

Splitting Vectors of Uneven Strings

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Suppose you have a vector of names such that the first three words in the vector contain relevant information, but there is a bunch of extra...
6 comments:
Monday, July 18, 2011

Avoiding Loops in R: An Example with Principal Minors

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Yesterday, I found myself wanting to compute a large subset of the second order principal minors of a matrix (diagonal-preserving minors; th...
8 comments:
Monday, June 20, 2011

Today's Assignment: Assignment

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A new R user quickly discovers that there are multiple ways to store information into an object -- the technical term for this is assignment...
1 comment:
Sunday, June 5, 2011

An application of aggregate() and merge()

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Today, I encountered an interesting problem while processing a data set of mine. My data have observations on businesses that are repeated ...
2 comments:
Monday, May 30, 2011

Recreational R: Simulating a Card Trick

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In this post, I simulate an interesting card trick, which was described by a friend of mine named Xan. Here's Xan's description of ...
3 comments:
Saturday, May 28, 2011

An Application of boot() to IV regression

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Bootstrapping standard errors can be a useful technique when obtaining closed form for the standard error formula is difficult or intractab...