Re: [R] Row-wise recurive function call

[David Winsemius]

On Nov 9, 2010, at 3:28 AM, Santosh Srinivas wrote:

Thanks this works. Only, I need to reference in the formula using indexes.

Then you need to use the indices inside plaFn.

playFn<- function (x){
  result = ((x[1]+6*x[2])/(3*x[3])+20)*x[4]
  return(result)
  }

-----Original Message-----
From: Dimitris Rizopoulos [mailto:d.rizopou...@erasmusmc.nl]
Sent: 09 November 2010 13:22
To: Santosh Srinivas
Cc: r-help@r-project.org
Subject: Re: [R] Row-wise recurive function call

try this:

apply(data.matrix(a), 1, playFn)


I hope it helps.

Best,
Dimitris


On 11/9/2010 8:32 AM, Santosh Srinivas wrote:

Dear Group,

I have a following dataset:

a

    A  B  C  D
1  22  3 31 40
2  26 31 36 32
3   3  7 49 16
4  24 40 27 26
5  20 45 47  0
6  34 43 11 18
7  48 48 24  2
8   3 16 39 48
9  20 49  7 21
10 17 36 47 10

dput(a)

structure(list(A = c(22L, 26L, 3L, 24L, 20L, 34L, 48L, 3L, 20L,
17L), B = c(3L, 31L, 7L, 40L, 45L, 43L, 48L, 16L, 49L, 36L),

C = c(31L, 36L, 49L, 27L, 47L, 11L, 24L, 39L, 7L, 47L), D = c(40L,

    32L, 16L, 26L, 0L, 18L, 2L, 48L, 21L, 10L)), .Names = c("A",
"B", "C", "D"), class = "data.frame", row.names = c(NA, -10L))

I have a function that works off EVERY individual ROW to throw a result.

Like

playFn<- function (x){
+ result = ((x$A+6*x$B)/(3*x$C)+20)*x$D
+ return(result)
+ }


I want to apply the function for every row .... can I use an "apply"
function ... tried but not been able to ...
e.g. print(rapply(a,playFn))

Please advise.

Thanks,
S

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--
Dimitris Rizopoulos
Assistant Professor
Department of Biostatistics
Erasmus University Medical Center

Address: PO Box 2040, 3000 CA Rotterdam, the Netherlands
Tel: +31/(0)10/7043478
Fax: +31/(0)10/7043014
Web: http://www.erasmusmc.nl/biostatistiek/

______________________________________________
R-help@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.

David Winsemius, MD
West Hartford, CT

______________________________________________
R-help@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.