CODEWITHSUNDEEP
rrandomsample
Hope
Hope

Reputation: 121

Error in sample.int(length(x), size, replace, prob) : invalid first argument

I am running the following lines of code and facing the above-mentioned error. Any ideas how to fix this ?

X <- NULL
S <- NULL
remove.value <- NULL
N <- seq.int(1, 25)
     
repeat {
  S <- sample(N, 1, replace = FALSE, prob = NULL)
  S
  if (S == 1) {
    remove.value <- c(S, S + 1)
  } else if (S == 25) {
    remove.value <- c(S, S - 1)
  } else {
    remove.value <- c(S - 1, S, S + 1)
  }
  remove.value
  N <- N [which(!(N %in% remove.value))]
  N
  if (is.null(N)) break
}

Upvotes: 5

Views: 37837

Answers (3)

Jakob
Jakob

Reputation: 1463

I'm also struggling with this in an entirely different setting. I think the answer of @DatamineR is correct. You can see this by trying:

sample(NULL, 1)
sample(integer(0), 1)

where you get the same error message:

Error in sample.int(length(x), size, replace, prob) : 
  invalid first argument

I still find this very misleading because neither of us called sample.int() ;) Doesn't make debugging easier. But for me at least that was the issue, we actually tried to sample from nothing.

Upvotes: 0

Tejas Kudva
Tejas Kudva

Reputation: 11

Removing the library Tidyverse solved this issue for me. The problem seems to be RStudio calling the sample.int() instead of simply sample(). Cheers!

Upvotes: 1

DatamineR
DatamineR

Reputation: 9618

It actually works as you intend. You can see it if you insert print(N)

> repeat{

    S<-sample(N ,1, replace = FALSE, prob = NULL)
    S
    if (S==1) {
        remove.value<-c(S,S+1)
    } else if (S==25) {
        remove.value<-c(S,S-1)
    }else {remove.value<-c(S-1,S,S+1)
    }
    remove.value

    N <- N [which(N %!in% remove.value)]          
    print(N)

    if (is.null(N)) break
}
 [1]  1  2  3  4  8  9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
 [1]  1  2  3  4  8  9 10 11 12 13 14 15 16 17 18 19 20 21 25
 [1]  1  2  3  4  8  9 13 14 15 16 17 18 19 20 21 25
 [1]  1  2  3  4  8  9 13 14 15 16 17 18 25
 [1]  1  2  3  4  8  9 16 17 18 25
[1]  1  2  3  4  8  9 25
[1]  1  2  8  9 25
[1]  8  9 25
[1] 8 9
integer(0)
Error in sample.int(length(x), size, replace, prob) : 
  invalid first argument

The error is caused by the final value of N, which is integer(0), and not NULL. If you use if (length(N)== 0) break instead of if (is.null(N)) break the code works without error message.

Upvotes: 5

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