Try

sapply(strsplit(sampleIDs, "_"), "[", 1)

HTH,
Jorge


On Wed, Dec 22, 2010 at 4:02 PM, maddox <> wrote:

>
> Dear Guru's
>
> My first steps with R have ground to a halt! I have a vector of sample
> identifiers
>
> > sampleIDs
>  [1] "D1_1"   "D1_2"   "D1_3"   "D1_4"   "D1_5"   "D1_6"   "D1_7"   "D1_8"
>  [9] "D1_9"   "D1_10"  "D1_11"  "D1_12"  "F1_13"  "F1_14"  "F1_15"  "F1_16"
> [17] "F1_17"  "F1_18"  "F1_19"  "F1_20"  "F1_21"  "F1_22"  "F1_23"  "F1_24"
> [25] "DDC_25" "DDC_26" "DDC_27" "DDC_28" "DDC_29" "DDC_30" "DDC_31"
> "DDC_32"
> [33] "DDC_33" "DDC_34" "DDC_35" "DDC_36"
>
> from which I've split the prefix identifier using strsplit
>
> > splitIDs <- strsplit( as.character(sampleIDs), "_")
> > splitIDs
> [[1]]
> [1] "D1" "1"
>
> [[2]]
> [1] "D1" "2"
>
> [[3]]
> [1] "D1" "3"
>
> [[4]]
> [1] "D1" "4"  etc
>
> I am now struggling to work with the prefix identifiers (D1, F1, DDC)
> because the only way I have figured out to access them is with
> splitIDs[[i]][1] i.e. it seems like I have to use a loop to get the
> identifiers into a factor and counted.
>
> Is there a vectorised solution someone can suggest?
> Or an alternative strategy .. these are early days using R for me!
> Thanks
>
>
> regards
>
> M
>
>
>
> --
> View this message in context:
> http://r.789695.n4.nabble.com/vectorised-recovery-of-strsplit-value-tp3161254p3161254.html
> Sent from the R help mailing list archive at Nabble.com.
>
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