R Writing a function input equal integer,but input maybe NA

Question

I want to write a function,Determine the input is equal to 1, but The input maybe includes (NA NULL).

> equals1 <- function(x){
+   return(x==1)
+ }

> equals1(1)
[1] TRUE
> equals1(Inf)
[1] FALSE
> equals1(NA)
[1] NA
> equals1(NULL)
logical(0)
> equals1(NaN)
[1] NA

I want is as follows：

equals1<-function(x){
   if(is.null(x)){
     return(FALSE)
     }else if(is.na(x)){
       return(FALSE)
     }else{return(x==1)}
}
c(equals1(1),equals1(Inf),equals1(NA),equals1(NULL),equals1(NaN))
# [1]  TRUE FALSE FALSE FALSE FALSE

Is there a simple function? Thanks!

Dan · Accepted Answer · 2019-03-08T18:22:28.003

identical can do this.

identical(1, 1)
#> [1] TRUE
identical(1, Inf)
#> [1] FALSE
identical(1, NA)
#> [1] FALSE
identical(1, NULL)
#> [1] FALSE
identical(1, NaN)
#> [1] FALSE

^{Created on 2019-03-08 by the reprex package (v0.2.1)}

You could write a simple wrapper like this:

equals1 <- function(x)identical(x, 1)

c(equals1(1),equals1(Inf),equals1(NA),equals1(NULL),equals1(NaN))
#> [1]  TRUE FALSE FALSE FALSE FALSE

^{Created on 2019-03-08 by the reprex package (v0.2.1)}

score 1 · Answer 2 · answered Mar 08 '19 at 18:43

according Numeric comparison difficulty in R this function can do it easily. note that identical(tan(pi/4),1) returns false.

    identical(tan(pi/4),1)
    #[1] FALSE
    eq<-function(x,y){
    isTRUE(all.equal(x, y))
    }
    eq(tan(pi/4),1)
    #[1] TRUE
    eq(3,1)
   #[1] FALSE
     eq(NA,1)
   #[1] FALSE
    eq(1, NaN)
   #[1] FALSE
    eq(1,1)
   #[1] TRUE
    eq(Inf,1)
  #[1] FALSE
    eq(NA,1)
  #[1] FALSE
    eq(NULL,1)
   #[1] FALSE

R Writing a function input equal integer,but input maybe NA

2 Answers2