From josh.m.ulrich at gmail.com  Sun Aug 10 20:28:44 2014
From: josh.m.ulrich at gmail.com (Joshua Ulrich)
Date: Sun, 10 Aug 2014 13:28:44 -0500
Subject: [Rd] "Fastest" way to merge 300+ .5MB dataframes?
In-Reply-To: <CAAjq1mepNYOdWv5yOD_iM3-BC9Pyek2He0rudXOiKX+nDS8cJg@mail.gmail.com>
References: <CAAjq1mepNYOdWv5yOD_iM3-BC9Pyek2He0rudXOiKX+nDS8cJg@mail.gmail.com>
Message-ID: <CAPPM_gRhOLiQsyk=+1-KYy2MKgQhPurUYw5NR5sQQkB=Q5ceXg@mail.gmail.com>

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
> ((? (x) (x x)) (? (x) (x x)))
> ?Life has become immeasurably better since I have been forced to stop
> taking it seriously.? --Thompson
>
> ______________________________________________
> R-devel at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-devel



[Rd] "Fastest" way to merge 300+ .5MB dataframes?
Joshua Ulrich