[R] function to filter identical data.fames using less than (<) and greater than (>)

[Jeff Newmiller]

You have not indicated why the subset function is insufficient for your needs...
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Sent from my phone. Please excuse my brevity.

Karl Brand <k.brand at erasmusmc.nl> wrote:

>Esteemed UseRs,
>
>I've got many biggish data frames which need a lot subsetting, like in 
>this example:
>
># example
>eg <- data.frame(A = rnorm(10), B = rnorm(10), C = rnorm(10), D =
>rnorm(10))
>egsub <- eg[eg$A < 0 & eg$B < 1 & eg$C > 0, ]
>egsub
>egsub2 <- eg[eg$A > 1 & eg$B > 0, ]
>egsub2
>
># To make this clearer than 1000s of lines of extractions with []
># I tried to make a function like this:
>
># func(data="eg", A="< 0", B="< 1", C="> 0")
>
># Which would also need to be run as
>
># func(data="eg", A="> 1", B="> 0", C=NA)
>#end
>
>Noteably:
>-the signs* "<" and ">" need to be flexible _and_ optional
>-the quantities also need to be flexible
>-column header names i.e, A, B and C don't need flexibility,
>i.e., can remain fixed
>* "less than" and "greater than" so google picks up this thread
>
>Once again i find just how limited my grasp of R is...Is do.call() the 
>best way to call binary operators like < & > in a function? Is an
>ifelse 
>statement needed for each column to make filtering on it optional?
>etc....
>
>Any one with the patience to show their working version of such a 
>funciton would receive my undying Rdulation. With thanks in advance,
>
>Karl