[R] extract submatrix with unique names

[David Barron]

This should do it, assuming you data is in a data frame called dat:

sel <- unique(dat$V1)
ix <- match(sel,dat$V1)
dat[ix,]


On 09/02/07, Glazko, Galina <Galina_Glazko at urmc.rochester.edu> wrote:
> Dear list,
>
>
>
> I have a table where first 3 columns are identical if the name in the
> first column is the same, and
>
> the number in N4 is slightly different for all identical names, like
> this:
>
> -------------------------------------------------------------------
>
> 29        Mm.1_at   3          +  93649936
>
> 30        Mm.1_at   3          +  93649990
>
> 31        Mm.1_at   3          +  93649993
>
> 32        Mm.1_at   3          +  93650001
>
> 33        Mm.1_at   3          +  93650010
>
> 34       Mm.10_at   4          + 147438101
>
> 35       Mm.10_at   4          + 147438192
>
> 36       Mm.10_at   4          + 147438214
>
> 37   Mm.100043_at   5          +  31602952
>
> 38   Mm.100043_at   5          +  31602982
>
> 39   Mm.100043_at   5          +  31603000
>
>  -------------------------------------------------------------------
>
>
>
> I need to select unique identifiers in column N 1, without paying
> attention to what is in column N4, taking the first number in N4
> corresponding to first unique ID in N1, like this:
>
> 29        Mm.1_at   3          +  93649936
>
> 34       Mm.10_at   4          + 147438101
>
> 37   Mm.100043_at   5          +  31602952
>
>
>
> Could someone tell me how to do it without FOR cycle over all IDs in N1?
>
>
>
> Thank you!
>
>
>
> Best regards
>
> Galina
>
>
>
>
>
>
>         [[alternative HTML version deleted]]
>
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>


-- 
=================================
David Barron
Said Business School
University of Oxford
Park End Street
Oxford OX1 1HP