appending to a list with dynamic names

r list append names
Alex picture Alex · May 16, 2012 · Viewed 17.2k times · Source

I have a list in R:

a <- list(n1 = "hi", n2 = "hello")

I would like to append to this named list but the names must be dynamic. That is, they are created from a string (for example: paste("another","name",sep="_")

I tried doing this, which does not work:

c(a, parse(text="paste(\"another\",\"name\",sep=\"_\")=\"hola\"")

What is the correct way to do this? The end goal is just to append to this list and choose my names dynamically.

Answer

Dason picture Dason · May 16, 2012

You could just use indexing with double brackets. Either of the following methods should work.

a <- list(n1 = "hi", n2 = "hello")
val <- "another name"
a[[val]] <- "hola"
a
#$n1
#[1] "hi"
#
#$n2
#[1] "hello"
#
#$`another name`
#[1] "hola"

 a[[paste("blah", "ok", sep = "_")]] <- "hey"
 a
#$n1
#[1] "hi"
#
#$n2
#[1] "hello"
#
#$`another name`
#[1] "hola"
#
#$blah_ok
#[1] "hey"

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