convert a vector to a list

Question

I have a vector like this

 c(\"1\", \"a\",\"b\")

and I\'d like to create this list

list(\"a\"=1,\"b\"=1)

is

Answer 1

For completeness, there is a simpler one-liner to do it in an "apply" style as requested:

as.list(sapply(x[-1],function(y) as.double(x[1])))

While not the fastest option, it is surely neat enough to deserve its place as an answer to the question. A significant speed-up is possible by not unnecessarily simplifying to a vector:

    library(microbenchmark)
    microbenchmark(times=20, 
               Charles=as.list(setNames(rep(as.numeric(x[1]), length(x) - 1), x[-1])),
               Gavin=makeList(x),
               Anon=sapply(x[-1],function(y) as.double(x[1]),simplify=FALSE)
)

Unit: microseconds
    expr    min      lq median      uq    max neval
 Charles 10.868 11.7735 11.774 12.3775 55.848    20
   Gavin 12.075 12.6795 13.132 13.8870 26.867    20
    Anon  6.643  7.0950  7.548  8.1520 17.811    20