trycatch scope in R-CodePudding

The following code is misbehaving. When I run it inside RStudio to test it, it's fine. I get a value for custom_vars which makes sense. As soon as I try to run this code with Knit, it returns the error every time.

I've tried playing aorund with the scope of custom_vars, but that doesnt' work either.

report_params <- "-summary-private-room-tenure-minmax-map-Analyse newVar group-Analyse oldVar group"

custom_vars <- tryCatch(
{
  a <- report_params
  a <- as.list(strsplit(a, "-")[[1]])
  a <- str_subset(a, pattern = "Analyse.*.group")
  
  if (length(a) > 0) {
    a <- sapply(strsplit(a, split=' group'  , fixed=TRUE), function(x) (x[1]))
    a <- sapply(strsplit(a, split='Analyse ', fixed=TRUE), function(x) (x[2]))
    custom_vars <- c(a)   # no return in try code!
  } else {
    ret <- c("zero legth")
    return( ret ) 
  }
}, error=function(e) {
    ret <- c("error")
    return( ret ) 
  }
)

If I chop out the trycatch, it works fine again. I've tried everything I can think of. This makes no sense whatsoever.

  a <- params$report_params
  a <- as.list(strsplit(a, "-")[[1]])
  a <- stringr::str_subset(a, pattern = "Analyse.*.group")
  
  if (length(a) > 0) {
    a <- sapply(strsplit(a, split=' group'  , fixed=TRUE), function(x) (x[1]))
    a <- sapply(strsplit(a, split='Analyse ', fixed=TRUE), function(x) (x[2]))
    custom_vars <- c(a)   # no return in try code!
  } else {
    custom_vars <- c("zero legth")
    # return( ret ) 
  }

CodePudding user response：

This is no function, no need for return. The return caused an error an triggered the error function in tryCatch.

custom_vars <- tryCatch({
    a <- report_params
    a <- as.list(strsplit(a, "-")[[1]])
    a <- stringr::str_subset(a, pattern="Analyse.*.group")
    if (length(a) > 0) {
      a <- sapply(strsplit(a, split=' group', fixed=TRUE), function(x) x[1])
      sapply(strsplit(a, split='Analyse ', fixed=TRUE), function(x) x[2])
    } else {
      "zero legth"
    }
  }, error=function(e) "error")

custom_vars
# [1] "newVar" "oldVar"