On Sun, Oct 26, 2008 at 8:06 PM, Duncan Murdoch <murdoch@stats.uwo.ca>wrote:

> On 26/10/2008 11:54 AM, John Lande wrote:
>
>> dear all,
>>
>> I have a little problem I am doing a loop, witha grep function. sometimes
>> it
>> happens that  have the following results
>>
>>  tmp <- grep("x", y)
>>> tmp
>>>
>> integer(0)
>>
>>
>> how can I recognise this outcome? is.na is not working of course, so what
>> else?
>>
>
> length(integer(0)) is zero.  If you get any matches, you'll get a longer
> result.
>
> Duncan Murdoch


thank you all,

both the strategies works fine

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