Posts Tagged ‘ ddply ’

Transforming subsets of data in R with by, ddply and data.table

June 11, 2012
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Transforming subsets of data in R with by, ddply and data.table

Transforming data sets with R is usually the starting point of my data analysis work. Here is a scenario which comes up from time to time: transform subsets of a data frame, based on context given in one or a combination of columns.As an example I use ...

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Custom Summary Stats as Dataframe or List

March 24, 2012
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Custom Summary Stats as Dataframe or List

On Stackoverflow I found this useful example on how to apply custom statistics on a dataframe and return the results as list or dataframe:somedata<- data.frame(               ...

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Comparison of ave, ddply and data.table

August 25, 2011
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Comparison of ave, ddply and data.table

A guest post by Paul Hiemstra. ———— Fortran and C programmers often say that interpreted languages like R are nice and all, but lack in terms of speed. How fast something works in R greatly depends on how it is implemented, i.e. which packages/functions does one use. A prime example, which shows up regularly on

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