[BioC] How to conditionally exit from a function?

[Robert Gentleman]

You exit from a function in one of two ways,
 call return, or fall off of the end (you can of course call return as
 the last line in the function).
 Functions *always* return a value (it is not always printed). It is
 the value of the last statement evaluated.

  So for the function below, if x<0 it returns the string "ouch",
  otherwise it returns x+10


 foo <- function(x) {
     if(x<0) return("ouch")
     y<-10
     x+y
  }
 

On Wed, May 21, 2003 at 05:48:01PM -0400, SHEN, WEICHENG . wrote:
> 
> Hi all:
> 
> I need to conditionally exit from a function, but don't know how. My example
> below indicates that when x>0, I wish to immediately exit from the function
> foo. I also with to return a flag value so that I could find out what
> happend in executing this function. What command I can use to make it
> happen? Your help and suggestions will be greatly appreciated. Thanks!
> 
> ============================================================================
> ===================================
> 
> foo<-function (x)
> {
> 	if (x>0) {
> 		do something ....
> 	} else {
> #		need to exit from this function at this point, and also
> return a flag value
> 	}
> 	do something ...
> }
> 
> Weicheng Shen, Ph.D.
> Senior Image Analyst
> Science Applications International Corporation
> 1710 SAIC Drive
> Mail Stop 2-6-9
> McLean, VA 22102
> (703) 676-4189
> 
> _______________________________________________
> Bioconductor mailing list
> Bioconductor at stat.math.ethz.ch
> https://www.stat.math.ethz.ch/mailman/listinfo/bioconductor

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| Robert Gentleman                 phone : (617) 632-5250                   |
| Associate Professor              fax:   (617)  632-2444                   |
| Department of Biostatistics      office: M1B20                            |
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