This is a companion to base::append() to help merging two lists or atomic vectors. prepend() is a clearer semantic signal than c() that a vector is to be merged at the beginning of another, especially in a pipe chain.

prepend(x, values, before = 1)

Arguments

x

the vector to be modified.

values

to be included in the modified vector.

before

a subscript, before which the values are to be appended.

Value

A merged vector.

Examples

x <- as.list(1:3) append(x, "a")
#> [[1]] #> [1] 1 #> #> [[2]] #> [1] 2 #> #> [[3]] #> [1] 3 #> #> [[4]] #> [1] "a" #>
prepend(x, "a")
#> [[1]] #> [1] "a" #> #> [[2]] #> [1] 1 #> #> [[3]] #> [1] 2 #> #> [[4]] #> [1] 3 #>
prepend(x, list("a", "b"), before = 3)
#> [[1]] #> [1] 1 #> #> [[2]] #> [1] 2 #> #> [[3]] #> [1] "a" #> #> [[4]] #> [1] "b" #> #> [[5]] #> [1] 3 #>