Validity checks are not working in my function-CodePudding

So I was starting to make my code

myplot2=function(d,a){
  if(!(is.data.frame(d)))
    stop("Error:Is not dataframe")
  
  if(a!= 1 || a!= 2){
    stop("Error:Has to be one or two")
  }
  
  
}

My problem is that this happens when i actually plug in 1 or into the data.

> myplot2(patients,1)
Error in myplot2(patients, 1) : Error:Has to be one or two
> myplot2(patients,2)
Error in myplot2(patients, 2) : Error:Has to be one or two

Why is my validity check failing to work properly?

CodePudding user response：

Rather than writing your own validity checks, another option is to make use of one of the available R packages. For example, using assertthat:

library(assertthat)
myplot2 <- function(d, a) {
    assert_that(is.data.frame(d))
    assert_that(length(a) == 1 & !a %in% 1:2)        
    "all good"    
}

# Examples
myplot2(NULL, 4)
# Error: d is not a data frame 
myplot2(mtcars, 1)
#  Error: length(a) == 1 & !a %in% 1:2 is not TRUE 
myplot2(mtcars, 0)
# [1] "all good"