[R] Sum up column values according to row id

arun smartpink111 at yahoo.com
Wed Apr 24 20:31:53 CEST 2013

```HI
Not sure whether this helps:
id dbh     h          g
1  FPE0164  36 13.62 0.10178760
2  FPE0164  31 12.70 0.07547676
21 FPE1127  57 18.85 0.25517586
13 FPE1127  39 15.54 0.11945906
12 FPE1127  34 14.78 0.09079203
6  FPE1127  32 15.12 0.08042477
5  FPE1127  28 14.13 0.06157522
15 FPE1127  27 13.50 0.05725553
19 FPE1127  25 13.28 0.04908739
11 FPE1127  19 11.54 0.02835287

library(plyr)
#      id          g
#1 FPE0164 0.08863218
#2 FPE1127 0.11078041

#       id          g
#1 FPE0164 0.08863218
#2 FPE1127 0.11078041

>Dear All,
>
>here a problem I think many of you can solve in few minutes.
>
>I have a dataframe which contains values of plot id, diameters, heigths and
>basal area of trees, thus columns names are: id | dbh | h | g
>
>head(ipso, n=10)        id dbh     h          g
>1  FPE0164  36 13.62 0.10178760
>2  FPE0164  31 12.70 0.07547676
>21 FPE1127  57 18.85 0.25517586
>13 FPE1127  39 15.54 0.11945906
>12 FPE1127  34 14.78 0.09079203
>6  FPE1127  32 15.12 0.08042477
>5  FPE1127  28 14.13 0.06157522
>15 FPE1127  27 13.50 0.05725553
>19 FPE1127  25 13.28 0.04908739
>11 FPE1127  19 11.54 0.02835287
>
>from here I need to calculate the mean of the six greater g_ith for
>each id_ith. The clauses are that:
>
>if length(id) >=6
>
>do the mean of the first six greaters g
>
>
>else
>do the mean of all the g_ith in the id_ith (in head print above e.g.
>for the id==FPE0164 do the mean of just these two values of g).
>
>The g are already ordered by id ascending and g descending using:
>
>ipso <- ipso[with(ipso, order(ipso\$id, -ipso\$g)), ] # Order for id
>ascending and g descending
>
>I tried a lot of for loops and tapply() without results.
>
>Can anyone help me to solve this?
>
>
>Best whishes
>
>Matteo

______________________________________________
[hidden email] mailing list
https://stat.ethz.ch/mailman/listinfo/r-help