break/exit script

Question

I have a program that does some data analysis and is a few hundred lines long.

Very early on in the program, I want to do some quality control and if there is not enough data, I want the program to terminate and return to the R console. Otherwise, I want the rest of the code to execute.

I've tried break, browser, and quit and none of them stop the execution of the rest of the program (and quit stops the execution as well as completely quitting R, which is not something I want to happen). My last resort is creating an if-else statement as below:

 if(n < 500){}

 else{*insert rest of program here*}

but that seems like bad coding practice. Am I missing something?

Answer 1

You can use the stopifnot() function if you want the program to produce an error:

For example:

foo <- function(x) {

 stopifnot(x > 500)

 # rest of program 

}