Estimated colleagues:
Here is a problem I am trying to solve: I have a data frame of this kind
df <-
data.frame(c("A","B","C","A","A","B"),
matrix(1:18,nrow=6,ncol=3))
rownames(df) <-
c("One","Two","Three","Four","Five","Six")
colnames(df) <-
c("C1","C2","C3","C4")
df
C1 C2 C3 C4
One A 1 7 13
Two B 2 8 14
Three C 3 9 15
Four A 4 10 16
Five A 5 11 17
Six B 6 12 18
I would like to obtain a data.frame or matrix in which rows with an
equal string on column "C1" are averaged. In the previous example,
rows
"One", "Four" and "Five" should be averaged
because the three have "A"
con C1. The resulting row should be: "A" 10/3 28/3 46/3
In SQL I think I could do this by selecting c1,c2,c3 and c4, grouping by
c1 and averaging c2, c3,and c4.
Is there some way to do this easily in R?
Thank you very much,
Federico
Estimated colleagues:
Here is a problem I am trying to solve: I have a data frame of this kind
df <-
data.frame(c("A","B","C","A","A","B"),
matrix(1:18,nrow=6,ncol=3))
rownames(df) <-
c("One","Two","Three","Four","Five","Six")
colnames(df) <-
c("C1","C2","C3","C4")
df
C1 C2 C3 C4
One A 1 7 13
Two B 2 8 14
Three C 3 9 15
Four A 4 10 16
Five A 5 11 17
Six B 6 12 18
I would like to obtain a data.frame or matrix in which rows with an
equal string on column "C1" are averaged. In the previous example,
rows
"One", "Four" and "Five" should be averaged
because the three have "A"
con C1. The resulting row should be: "A" 10/3 28/3 46/3
In SQL I think I could do this by selecting c1,c2,c3 and c4, grouping by
c1 and averaging c2, c3,and c4.
Is there some way to do this easily in R?
Thank you very much,
Federico
> I would like to obtain a data.frame or matrix in which rows with an > equal string on column "C1" are averaged. In the previous example, rows > "One", "Four" and "Five" should be averaged because the three have "A" > con C1. The resulting row should be: "A" 10/3 28/3 46/3I think this is waht you are looking for: aggregate(df[-1], by=list(C1=df$C1), mean) cu Philipp -- Dr. Philipp Pagel Lehrstuhl f?r Genomorientierte Bioinformatik Technische Universit?t M?nchen Wissenschaftszentrum Weihenstephan 85350 Freising, Germany and Institut f?r Bioinformatik und Systembiologie / MIPS Helmholtz Zentrum M?nchen - Deutsches Forschungszentrum f?r Gesundheit und Umwelt Ingolst?dter Landstrasse 1 85764 Neuherberg, Germany http://mips.gsf.de/staff/pagel