When assign a value to a position in a vector, how do you pass the name of the value as well?-CodePudding

For example,

var <- structure(character(3), names=character(3))
v2 <- "p2"; names(v2) <- "name p2"

If I do the following:

var[2] <- v2

Only the value "p2" is passed into the vector but not the name "name p2".

What I want is a one-line syntax to do the following:

var[2] <- v2; names(var)[2] <- names(v2)

CodePudding user response：

var <- structure(character(3), names=letters[1:3])
v2 <- "p2"; names(v2) <- "name p2"

vslice <- function(x, i) x[i]
`vslice<-` <- function(x, i, value){
  x[i] <- value
  names(x)[i] <- names(value)
  x
}

vslice(var, 2)
#>  b 
#> ""
vslice(var, 2) <- v2
var
#>       a name p2       c 
#>      ""    "p2"      ""

^{Created on 2021-11-11 by the reprex package (v2.0.1)}

CodePudding user response：

You could just capture the steps in a function:

vec_names_merge <- function(x, y, pos) {
  y[pos] <- x; 
  names(y)[pos] <- names(x)
  y
}

vec_names_merge(v2, var, 2)
        name p2         
     ""    "p2"      ""

CodePudding user response：

One way to do this is to grow the named vector by appending values rather than inserting them by index value. You could insert by inserting a value into an existing vector, but it is cumbersome:

var <- c(names_p1="p1")
var <- c(var, names_p3="p3")
add <- c(names_p2="p2")
var <- c(var[1], add, var[2])
var
# names_p1 names_p2 names_p3 
#     "p1"     "p2"     "p3"