Dear Hollie,
ifelse() is one alternative in this particular case:


# Some data
age<- c(46,47,43,46,47,59,50,54,59,60)

ifelse(age<=46, 1,
        ifelse( age>46 & age<=58 , 2, 3) )
[1] 1 2 1 1 2 3 2 2 3 3


See ?ifelse for more details.

HTH,

Jorge


On Thu, Apr 23, 2009 at 8:07 PM, Giggles_Fairy
<giggles_fairy16@hotmail.com>wrote:

>
> I have a set of data that includes various data columns. One if the
> survival
> time and another if a continuous variable of ages. I want to put the ages
> into intervals so that I can then perform the Kalpan Meier test. I am
> trying
> to use the following code to build a column with the age group numbers in
>
> agecatagory<-c( )
> for (i in 1:137)
> {
> {
> if(age[i]<=46)  {agecat[i]<-1}
> if(age[i]>46 & age[i]<= 58) {agecat[i]<-2}
> if(age[i]>58) {agecat[i]<-3}
> }
> agecatagory<-c(agecatagory, agecat[i])
> }
>
> I have been getting various errors for various things and have finally got
> it so that only one error comes up
> Error in if (age[i] <= 46) { : missing value where TRUE/FALSE needed
>
> Could anyone pleaseeeeeee shed some light on this for me and tell em where
> I
> am going wrong. I am sure it is just a minor thing but I cant for the life
> of me figure it out!
>
> Your replies will be very much appreciated!
>
> Hollie
> --
> View this message in context:
> http://www.nabble.com/Help-with-for-if-loop-tp23207428p23207428.html
> Sent from the R help mailing list archive at Nabble.com.
>
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>

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