[R] how to assign a value to a specific position of a list

[peter dalgaard]

assign(paste("list_", i, "[[1]]", sep = ""), 5) creates a new variable with a funny name. 

You'd have to parse() and eval() to make that work, something like

eval(parse(text=paste("list_",i,"[[1]]<-",5, sep="")))

However,
-------
> fortunes::fortune("parse")

If the answer is parse() you should usually rethink the question.
   -- Thomas Lumley
      R-help (February 2005)
-------

It is much easier to handle this using a data structure containing a list of lists:

l <- rep(list(list()), 10)
for ( i in 1:10 ) 
   l[[i]][[1]] <- 5
 
> On 30 Apr 2017, at 17:17 , Jinsong Zhao <jszhao at yeah.net> wrote:
> 
> Hi there,
> 
> I have a problem with assign(). Here is the demo code:
> 
> for (i in 1:10) {
>   # create a list with variable name as list_1, list_2, ..., etc.
>   assign(paste("list_", i, sep = ""), list())
>   # I hope to assign 5 to list_?[[1]], but I don't know how to code it.
>   # list_1[[1]] <- 5 # works, however
>   assign(paste("list_", i, "[[1]]", sep = "", 5) # does not work
> }
> 
> How to do? Is there any alternatives? Many thanks!
> 
> Best,
> Jinsong
> 
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-- 
Peter Dalgaard, Professor,
Center for Statistics, Copenhagen Business School
Solbjerg Plads 3, 2000 Frederiksberg, Denmark
Phone: (+45)38153501
Office: A 4.23
Email: pd.mes at cbs.dk  Priv: PDalgd at gmail.com