Applying a function successively in R

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At the R in Finance conference Paul Teetor gave a fantastic talk about Fast(er) R Code. Paul mentioned the common higher-order function Reduce, which I hadn’t used before.

Reduce allows me to apply a function successively over a vector.

What does that mean? Well, if I would like to add up the figures 1 to 5, I could say: add orReduce(add, 1:5)

Now this might not sound exciting, but Reduce can be powerful. Here is an example with googleVis. To merge two charts I use the function gvisMerge, which takes two charts and wraps them up in an HTML table. Hence, to create a page with a line-, column- area- and bar chart I could use:

pp

or use Reduce instead:

pr

library(googleVis)
data(OpenClose)
ops

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