[R] how to call a function for each row

[Florent D.]

if you want to store the result in a column of your data.frame:

within(df, Y <- 6*X1+7*X2+8*X3)


On Wed, Nov 30, 2011 at 9:59 AM, David L Carlson <dcarlson at tamu.edu> wrote:
> Isn't this even easier?
>
>> X1 <- c(1:3)
>> X2 <- c(3, 4, 6)
>> X3 <- c(5, 6, 1)
>> Y <- 6*X1 + 7*X2 + 8*X3
>> Y
> [1] 67 88 68
>
> Or if you really need a function:
>
>> MakeY <- function(x, y, z) 6*x + 7*y + 8*z
>> MakeY(X1, X2, X3)
> [1] 67 88 68
>
>
> ----------------------------------------------
> David L Carlson
> Associate Professor of Anthropology
> Texas A&M University
> College Station, TX 77843-4352
>
>
>
> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org] On
> Behalf Of R. Michael Weylandt
> Sent: Wednesday, November 30, 2011 8:17 AM
> To: arunkumar1111
> Cc: r-help at r-project.org
> Subject: Re: [R] how to call a function for each row
>
> Read ?apply
>
> This is easiest:
>
> df <- matrix(c(1,2,3,3,4,6,5,6,1), 3)
> apply(df, 1, function(x) 6*x[1]+7*x[2]+8*x[3])
>
> But it's much more efficient to do it with matrix multiplication. In keeping
> with the best of tradition, this is left as an exercise to the reader.
>
> Michael
>
> On Wed, Nov 30, 2011 at 8:10 AM, arunkumar1111 <akpbond007 at gmail.com> wrote:
>> Hi
>>
>>  I have  a data-frame which look like this
>>
>> X1 X2 X3
>> 1   3  5
>> 2   4  6
>> 3   6  1
>>
>> I want to apply a formula Y=6*X1 + 7*X2 + 8*X3  for every row
>>
>>
>> Thanks in Advance
>>
>>
>>
>>
>>
>>
>>
>> --
>> View this message in context:
>> http://r.789695.n4.nabble.com/how-to-call-a-function-for-each-row-tp41
>> 22906p4122906.html Sent from the R help mailing list archive at
>> Nabble.com.
>>
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>>
>
> ______________________________________________
> R-help at r-project.org mailing list
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> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.