R help - Oct 2008 - help with doing a manipulation on a column of a data frame based on another column

#this is my stab at - I am sure that I am missing something.  If this
doesn't make sense then please ask for more details.  #This may show
my low level of programing knowledge

hester. <- c(1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4)
value <- rnorm(16)
x <- data.frame(value, hester.)

z <-
(if(x[,"hester."]==1){
x[,"value"]*6.250}
else
if(x[,"hester."]==2){
x[,"value"]*3.125}
else
if(x[,"hester."]==3){
x[,"value"]*2.100}
else
if(x[,"hester."]==4){
x[,"value"]*1.600})

thanks

stephen

-- 
Stephen Sefick
Research Scientist
Southeastern Natural Sciences Academy

Let's not spend our time and resources thinking about things that are
so little or so large that all they really do for us is puff us up and
make us feel like gods.  We are mammals, and have not exhausted the
annoying little problems of being mammals.

								-K. Mullis

On 29/10/2008, at 2:41 PM, stephen sefick wrote:
> #this is my stab at - I am sure that I am missing something.  If this
> doesn't make sense then please ask for more details.  #This may show
> my low level of programing knowledge
>
> hester. <- c(1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4)
> value <- rnorm(16)
> x <- data.frame(value, hester.)
>
> z <-
> (if(x[,"hester."]==1){
> x[,"value"]*6.250}
> else
> if(x[,"hester."]==2){
> x[,"value"]*3.125}
> else
> if(x[,"hester."]==3){
> x[,"value"]*2.100}
> else
> if(x[,"hester."]==4){
> x[,"value"]*1.600})

Does this do what you want?

  > h <- rep(1:4,each=4)
  > z <- c(6.25,3.125,2.1,1.6)[match(h,1:4)]
  > x <- data.frame(hester.=h,value=z)

	cheers,

		Rolf Turner


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> #this is my stab at - I am sure that I am missing something.  If this
> doesn't make sense then please ask for more details.  #This may show
> my low level of programing knowledge
>
> hester. <- c(1,1,1,1,2,2,2,2,3,3,3,3,4,4,4,4)
> value <- rnorm(16)
> x <- data.frame(value, hester.)
>
> z <-
> (if(x[,"hester."]==1){
> x[,"value"]*6.250}
> else
> if(x[,"hester."]==2){
> x[,"value"]*3.125}
> else
> if(x[,"hester."]==3){
> x[,"value"]*2.100}
> else
> if(x[,"hester."]==4){
> x[,"value"]*1.600})

Does this do what you want?

  > h <- rep(1:4,each=4)
  > z <- c(6.25,3.125,2.1,1.6)[match(h,1:4)]
  > x <- data.frame(hester.=h,value=z)

	cheers,

		Rolf Turner

---------------------------------------------
I suspect some random values should be included, making the code
:
> h <- rep(1:4,each=4)
  > z <- c(6.25,3.125,2.1,1.6)[match(h,1:4)]
  > x <- data.frame(hester.=h,value=z*rnorm(16))

Kind regards
Joris