On Apr 26, 2009, at 8:02 AM, Alessandro wrote:
Dear User,
thank for the attention. I have a data.frame with 5 columns (ex:ID,
a1,a2,a3,a4) and 1000 rows. I wish to find the absolute max value
for all
data.frame and save a new data.frame with the row where is that
value. Ex:
ID: 1,2,3,4,5,6,7,8,9,10
a1:1,2,3,4,5,6,7,8,9,10
a2:11,12,13,14,15,16,17,18,19,20
a3:21,22,23,24,25,26,27,28,29,30
a4:31,32,33,34,35,36,37,38,39,40
The max value in the four columns (a1,a2,a3,a4) is 40. The new
data.frame is
ID:10
A1:10
A2:20
A3:30
A4 :40
df <- data.frame(ID= c( 1,2,3,4,5,6,7,8,9,10),
a1 =c(1,2,3,4,5,6,7,8,9,10),
a2 =c(11,12,13,14,15,16,17,18,19,20),
a3 = c(21,22,23,24,25,26,27,28,29,30),
a4 = c(31,32,33,34,35,36,37,38,39,40) )
df
---output---
ID a1 a2 a3 a4
1 1 1 11 21 31
2 2 2 12 22 32
3 3 3 13 23 33
4 4 4 14 24 34
5 5 5 15 25 35
6 6 6 16 26 36
7 7 7 17 27 37
8 8 8 18 28 38
9 9 9 19 29 39
10 10 10 20 30 40
-----
apply(df, 2, max)
# If you want the names to be as specified, then look at the colnames
function, but at this point I am concerned that I may have already
done too much of you homework.
--output---
ID a1 a2 a3 a4
10 10 20 30 40
----
max(df)
[1] 40
--
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
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