CODEWITHSUNDEEP
r
mountainlake
mountainlake

Reputation: 39

Calling from character to numeric data

I'm working on R and need to select randomly a set of parameters from the following sample:

params1 <- c(a=1, b=2, c=3)
params2 <- c(a=4, b=5, c=6)
params3 <- c(a=7, b=8, c=9)

selected<-sample(c(1,2,3),size=1, replace=TRUE, 
           prob=c(0.33,0.33,0.33))`

However when I use the following comand, 

params<-paste("params",selected,sep="")

params is a character and not the numeric set of parameters that I need.

Maybe this question is very easy, but I am used to matlab language.

Upvotes: 1

Views: 48

Answers (2)

akrun
akrun

Reputation: 887038

We can use get to get the value of the object.

get(paste("params",selected,sep=""))

If there are multiple objects, use mget instead of get and it will return a list of values.

Or instead of sample on 1:3, we can directly apply on the 'params'

sample(mget(ls(pattern='^params\\d+')), size=1,
              prob=c(0.33,0.33,0.33))

Upvotes: 1

joran
joran

Reputation: 173547

The correct way to do this sort of thing in R is not to keep param1, param2, etc as isolated objects, but put them in a named list:

plist <- list(param1 = c(a=1, b=2, c=3),
              param2 = c(a=4, b=5, c=6),
              param3 = c(a=7, b=8, c=9))

And then you can select which one you want with numeric indexing, i.e. plist[[selected]], or by name plist[[paste0("param",selected)]].

Upvotes: 2

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