hi catalin, i thought this was a great question and could not find a good
answer on stackoverflow.com, so i have started this thread which asks the
question formally.  i have also provided one answer that should be
sufficient for you, but others may weigh in as well

http://stackoverflow.com/questions/14800161/how-to-find-the-top-n-values-by-group-or-within-category-groupwise-in-an-r-dat

hope this helps :)


On Sun, Feb 10, 2013 at 5:42 AM, andrija djurovic <djandrija@gmail.com>wrote:

> Hi,
>
> see function ?head or "[".
>
> If DF is you data frame, top n values of DF you can select with head(DF, n)
> or DF[1:n, ]...
>
> Andrija
>
> On Sun, Feb 10, 2013 at 11:31 AM, catalin roibu <catalinroibu@gmail.com
> >wrote:
>
> > Dear R users,
> > I have a problem. I don't know how to select the top 10 (n) values for
> each
> > classes.
> > Thank you!
> > My data is like this:
> >  row.names proc cls  7271 568,03338 0,5  7270 554,68458 0,5  7269
> 510,20638
> > 0,5  7268 485,59969 0,5  7267 421,92852 0,5  7272 410,12101 0,5  3414
> > 409,71429 0,5  3452 402,78699 0,5  3451 401,28114 0,5  3450 361,80607 0,5
> > 3413 360,29883 0,5  3449 352,90043 0,5  3453 339,36457 0,5  7266
> 331,38278
> > 0,5  3415 327,89374 0,5  3454 324,4335 0,5  3412 291,95631 0,5  4770
> > 274,12649 0,5  3455 274,09326 0,5  6030 264,72652 0,5  4772 264,17632 0,5
> > 6031 261,19403 0,5  3411 255,50239 0,5  4773 241,50886 0,5  3447
> 237,78135
> > 0,5  3448 232,9554 0,5  4774 232,92985 0,5  7273 229,18868 0,5  6028
> > 225,24249 0,5  11839 220,61201 0,5  4771 218,94856 0,5  6026 218,7 0,5
> > 11838 213,44438 0,5  3410 209,35622 0,5  6027 206,68399 0,5  6029
> 206,10424
> > 0,5  11837 205,28621 0,5  6025 201,21227 0,5  1042 199,78883 0,5  4775
> > 197,29348 1  7265 195,07017 1  4776 175,90948 1  10725 175,60525 1  10724
> > 173,2342 1  3456 172,44641 1  11589 170,2784 1  7190 169,53567 1  11799
> > 169,19097 1  6024 169,09314 1  3416 168,39827 1  10726 165,25617 1  11840
> > 164,43032 1  11800 162,7957 1  11590 155,31572 1  1043 154,6438 1  11841
> > 153,80017 1  7189 152,26293 1  11588 151,07692 1  11798 151,0658 1  3446
> > 147,0405 1  11836 147,02381 1  7188 142,01954 1  11835 140,95302 1  5994
> > 138,06452 1  3523 137,98974 1  11797 137,57633 1  11728 137,49488 1  7192
> > 136,87805 1  11731 135,10162 1  5995 132,41401 1  3096 131,11658 1  7191
> > 131
> > 1  3525 128,74521 1  11801 128,57672 1  7264 128,24427 1  3099 128,20339
> > 1,5
> > 11377 127,53474 1,5  10948 126,81159 1,5  11834 126,67371 1,5  11378
> > 126,42474 1,5  11842 126,27561 1,5  4777 126,26175 1,5  10949 124,39545
> 1,5
> > 3524 123,64685 1,5  5993 123,39782 1,5  10943 123,27824 1,5  3409
> 122,84964
> > 1,5  10942 121,28378 1,5  11730 118,13305 1,5  10702 117,91925 1,5  11796
> > 117,5239 1,5  4769 117,38123 1,5  11587 116,49326 1,5  7223 114,19009 1,5
> > 3396 114,16026 1,5  3097 113,99856 1,5  3526 113,97446 1,5  11376
> 113,58453
> > 1,5  11591 113,46819 1,5  7163 110,99291 1,5  1044 110,76636 1,5  3457
> > 110,35221 1,5  10944 109,87002 1,5  11802 109,64554 1,5  3100 109,2207
> 1,5
> > 6023 109,01308 1,5  10947 108,45018 1,5  3098 108,20547 1,5  11593
> 108,0705
> > 1,5  3458 108,03632 1,5  11592 107,53228 1,5  11729 107,35615 1,5  3095
> > 107,24396 1,5  7222 106,02489 1,5  10945 105,24515 1,5  3101 104,75914
> 1,5
> > 10946 103,92964 1,5  5199 103,81953 1,5  11832 103,6405 1,5  11333
> > 103,53049
> > 1,5  7220 102,87019 1,5  11379 102,66542 1,5  3104 102,5464 1,5  10941
> > 101,4321 1,5  5198 100,62386 1,5  11375 99,731904 1,5  11803 99,08347 1,5
> > 7187 98,076923 1,5  7221 96,853367 1,5  11356 96,797409 1,5  7167
> 96,326062
> > 1,5  11715 95,902613 1,5  11727 95,79491 1,5  7166 95,747126 1,5  7253
> > 95,56314 2  10703 95,379713 2  3102 94,146825 2  11732 93,961076 2  5992
> > 93,93088 2  11833 93,902859 2  7224 93,114144 2  3103 93,022202 2  7164
> > 92,4972 2  12180 91,891892 2  11355 90,585242 2  10679 90,491487 2  7252
> > 89,664613 2  3105 89,112093 2  5200 88,798701 2  5203 86,954782 2  11354
> > 86,686174 2  11357 86,655518 2  10940 86,422977 2  11594 86,189863 2
>  12179
> > 86,122178 2  7263 84,991274 2  10520 84,532374 2  11733 83,963012 2  7225
> > 83,766234 2  11586 83,194864 2
> >
> >
> > Catalin-Constantin ROIBU
> > Forestry engineer, PhD
> > Forestry Faculty of Suceava
> > Str. Universitatii no. 13, Suceava, 720229, Romania
> > office phone     +4 0230 52 29 78, ext. 531
> > mobile phone   +4 0745 53 18 01
> >                        +4 0766 71 76 58
> > FAX:                +4 0230 52 16 64
> > silvic.usv.ro
> >
> >         [[alternative HTML version deleted]]
> >
> > ______________________________________________
> > R-help@r-project.org mailing list
> > https://stat.ethz.ch/mailman/listinfo/r-help
> > PLEASE do read the posting guide
> > http://www.R-project.org/posting-guide.html<
> http://www.r-project.org/posting-guide.html>
> > and provide commented, minimal, self-contained, reproducible code.
> >
>
>         [[alternative HTML version deleted]]
>
> ______________________________________________
> R-help@r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
> http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>

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