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? Thanks for your attention Best whishes Matteo [[alternative HTML version deleted]]
Something like this?
mean6 <- function(x) {
if (length(x) < 6) {
mn <- mean(x)
} else {
mn <- mean(x[1:6])
}
return(mn)
}
aggregate(g~id, ipso, mean6)
-------------------------------------
David L Carlson
Associate Professor of Anthropology
Texas A&M University
College Station, TX 77840-4352
-----Original Message-----
From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-project.org]
On
Behalf Of Matteo Mura
Sent: Wednesday, April 24, 2013 7:57 AM
To: r-help at r-project.org
Subject: [R] Sum up column values according to row id
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?
Thanks for your attention
Best whishes
Matteo
[[alternative HTML version deleted]]
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HI Not sure whether this helps: ipso<- read.table(text=" ?? 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 ",sep="",header=TRUE,stringsAsFactors=FALSE) library(plyr) ddply(ipso,.(id),summarize,g=mean(head(g,6))) ?# ???? id????????? g #1 FPE0164 0.08863218 #2 FPE1127 0.11078041 aggregate(g~id,ipso,function(x) mean(head(x,6))) #?????? 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? > >Thanks for your attention > >Best whishes > >Matteo______________________________________________ [hidden email] 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.