“dims [product xx] do not match the length of object [xx]” error in using R function `outer`

Question

x <- 1:9
names(x) <- paste0(\"x\",x)
y <- 2:5
names(y) <- paste0(\"y\",y)

fun1      <-function(a, b) {paste(class(a),b, sep = \"**\")} #works
funErro         


        

Answer 1

I think this comes because the resulting matrix from outer expects to be the same dimensions as your inputs, however, class(a) is only length 1, therefor the matrix dimensions do not match. Try

funError2 <- function(a,b){paste(rep(class(a), length(a)),rep(class(b), length(b)), sep = "**")}
outer(x,y, "funError2")
#>    y2                 y3                 y4                
#> x1 "integer**integer" "integer**integer" "integer**integer"
#> x2 "integer**integer" "integer**integer" "integer**integer"
#> x3 "integer**integer" "integer**integer" "integer**integer"
#> x4 "integer**integer" "integer**integer" "integer**integer"
#> x5 "integer**integer" "integer**integer" "integer**integer"
#> x6 "integer**integer" "integer**integer" "integer**integer"
#> x7 "integer**integer" "integer**integer" "integer**integer"
#> x8 "integer**integer" "integer**integer" "integer**integer"
#> x9 "integer**integer" "integer**integer" "integer**integer"
#>    y5                
#> x1 "integer**integer"
#> x2 "integer**integer"
#> x3 "integer**integer"
#> x4 "integer**integer"
#> x5 "integer**integer"
#> x6 "integer**integer"
#> x7 "integer**integer"
#> x8 "integer**integer"
#> x9 "integer**integer"

Created on 2018-09-13 by the reprex package (v0.2.0).