[Rd] "Fastest" way to merge 300+ .5MB dataframes?
josh.m.ulrich at gmail.com
Sun Aug 10 20:28:44 CEST 2014
The same comment Jeroen Ooms made about your last email also applies
to this one: it is better suited to R-help.
Joshua Ulrich | about.me/joshuaulrich
FOSS Trading | www.fosstrading.com
On Sun, Aug 10, 2014 at 1:18 PM, Grant Rettke <gcr at wisdomandwonder.com> wrote:
> Good afternoon,
> Today I was working on a practice problem. It was simple, and perhaps
> even realistic. It looked like this:
> • Get a list of all the data files in a directory
> • Load each file into a dataframe
> • Merge them into a single data frame
> Because all of the columns were the same, the simplest solution in my
> mind was to `Reduce' the vector of dataframes with a call to
> `merge'. That worked fine, I got what was expected. That is key
> actually. It is literally a one-liner, and there will never be index
> or scoping errors with it.
> Now with that in mind, what is the idiomatic way? Do people usually do
> something else because it is /faster/ (by some definition)?
> Kind regards,
> Grant Rettke | ACM, ASA, FSF, IEEE, SIAM
> gcr at wisdomandwonder.com | http://www.wisdomandwonder.com/
> “Wisdom begins in wonder.” --Socrates
> ((λ (x) (x x)) (λ (x) (x x)))
> “Life has become immeasurably better since I have been forced to stop
> taking it seriously.” --Thompson
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