[R] Selecting vector elements using other vectors

[Charles C. Berry]

See

 	?is.element
 	?%in%

HTH,

Chuck
On Wed, 29 Apr 2009, 00alastair00 wrote:

>
> Dear R-Help,
>
> I have a data frame and a vector
>
> df=data.frame(Letter=c("Z","Q","R","A","E","F"), Number=c(11,32,4,1,9,3))
> v=c("C","Q","R","A","E")
>
>> From df, I'd like to construct a subset of the field "Number", with
> deletions dictated by the vector, v, of letters.  I've succeeded in doing
> this for a single deletion (for example Letter="Q") with the following
>
> df$Number[df$Letter != v[2]]
>
> but am struggling do more than one at a time.  For example,
>
> df$Number[df$Letter != v[2:5]]
>
> gives the error:   Warning messages: 1: Is.na(e1) | is.na(e2) : longer
> object length is not a multiple of shorter object length 2: In.....  Perhaps
> there is a much easier way to approach this...
>
> Any help would be greatly appreciated!
>
> Alastair
> -- 
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>
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Charles C. Berry                            (858) 534-2098
                                             Dept of Family/Preventive Medicine
E mailto:cberry at tajo.ucsd.edu	            UC San Diego
http://famprevmed.ucsd.edu/faculty/cberry/  La Jolla, San Diego 92093-0901