[R] wrong name of input file and goto like function

[Bansal, Vikas]

Dear all,

I have a question and need your help please.
I have the following code which is asking user to enter the name of their file.

define<- function() 
 { 
 readline("enter the name of your file: ") 
 } 

df=read.table(define(),fill=T,sep="\t",colClasses = "character")

Now I want if user will input wrong name of file the code should not end and it should show a message-

if()
{
 print("wrong name of the file Please enter again ")

 }

now I want to ask what should be the condition of if so that if user will input wrong file name it will show this message and then i want to use something like goto so that it should again start with the code which is before if condition-

df=read.table(define(),fill=T,sep="\t",colClasses = "character")




so the code should be-

define<- function(x) 
 { 
 readline("enter the name of your file: ") 
 } 

df=read.table(define(),fill=T,sep="\t",colClasses = "character")           ##starline


if(## some condition here)
{
 print("wrong name of the file Please enter again ")
## some goto function so that it should goto (starline)
 }





 

Thanking you,
Warm Regards
Vikas Bansal
Msc Bioinformatics
Kings College London