R help - Jun 2007 - R behaviour related to user input (readline()) and run selection

When I run the below section of code I get the following error: 

 

       Error in if (co == "A" || co[1] == "O") { : 

              missing value where TRUE/FALSE needed

 

When I run the code in two parts where I first get the user's input

then afterwards run the if/else section, there is no problem.

 

Is there a way to stop the "run selection" process until the user

has input a value?

 

------------------------------------------------------------------------
-----



       calc_option <- function(){

              msg <- cat("Please select an option:\n","
'O'ne or 'A'll':
")

              co <- readline(msg)

              

              switch(co,

                     O = "O", o = "O",

                     A = "A", a = "A"

              )

       }

       

       co <- calc_option()



       if (co == "A" || co[1] == "O") {

              print(paste("calc_option = ", co))

       } else {

              print("calc_option is not acceptable")

       }





Thanks,



- Bruce

-------------- next part --------------


**********************************************************************
Please be aware that, notwithstanding the fact that the pers...{{dropped}}

First of all you don't appear to be returning anything from your function,
so 'co' is NULL and your 'if' statement fails.  You were also
probably
cut/paste the code in, and the readline was reading from the statements you
pasted.  Try sourcing in the code.

On 6/25/07, Bernzweig, Bruce (Consultant) <bbernzwe@bear.com>
wrote:
>
> When I run the below section of code I get the following error:
>
>
>
>       Error in if (co == "A" || co[1] == "O") { :
>
>              missing value where TRUE/FALSE needed
>
>
>
> When I run the code in two parts where I first get the user's input
>
> then afterwards run the if/else section, there is no problem.
>
>
>
> Is there a way to stop the "run selection" process until the user
>
> has input a value?
>
>
>
> ------------------------------------------------------------------------
> -----
>
>
>
>       calc_option <- function(){
>
>              msg <- cat("Please select an option:\n","
'O'ne or 'A'll':
> ")
>
>              co <- readline(msg)
>
>
>
>              switch(co,
>
>                     O = "O", o = "O",
>
>                     A = "A", a = "A"
>
>              )
>
>       }
>
>
>
>       co <- calc_option()
>
>
>
>       if (co == "A" || co[1] == "O") {
>
>              print(paste("calc_option = ", co))
>
>       } else {
>
>              print("calc_option is not acceptable")
>
>       }
>
>
>
>
>
> Thanks,
>
>
>
> - Bruce
>
>
>
>
> **********************************************************************
> Please be aware that, notwithstanding the fact that the pers...{{dropped}}
>
>
> ______________________________________________
> R-help@stat.math.ethz.ch mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>
>

-- 
Jim Holtman
Cincinnati, OH
+1 513 646 9390

What is the problem you are trying to solve?

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