[R] integer(0) and NA do not equal FALSE

Hi, A noobie question: I'm simply trying to run a conditional statement that evaluates if a substring is found within a larger string. I find that if it IS found, my function returns TRUE (great!), but if not, the condition does not evaluate to FALSE. ex): if( grep(hi, hop, fixed = TRUE) )

Re: [R] integer(0) and NA do not equal FALSE

try using 'grepl' if( grepl(hi, hop, fixed = TRUE) ){ + print('yes, your substring is in your string') + } else print('no, your substring is not in your string') [1] no, your substring is not in your string On Sat, Dec 19, 2009 at 3:47 PM, Jonathan jonsle...@gmail.com wrote: Hi, A

Re: [R] integer(0) and NA do not equal FALSE

Hi Jonathan, grep() returns a vector giving either the indices of the elements of 'x' that yielded a match or, if 'value' is 'TRUE', the matched elements of 'x' (quoting from the help page, see ?grep). So you probably want to test whether this vector is empty or not - in other words,

Re: [R] integer(0) and NA do not equal FALSE

Thanks, Jim and Stephen! On Sat, Dec 19, 2009 at 3:57 PM, jim holtman jholt...@gmail.com wrote: try using 'grepl' if( grepl(hi, hop, fixed = TRUE) ){ + print('yes, your substring is in your string') + } else print('no, your substring is not in your string') [1] no, your substring

Re: [R] integer(0) and NA do not equal FALSE

Hi Jonathan, The function isTRUE is useful for this sort of thing: isTRUE(pmatch(hi, hop)) evaluates to FALSE. --Gray On Sat, Dec 19, 2009 at 12:47 PM, Jonathan jonsle...@gmail.com wrote: Hi,   A noobie question:  I'm simply trying to run a conditional statement that evaluates if a substring