Dear Jim,
17.03.2011 20:54, Jim Silverton wrote:
I have a matrix say:
23 1
12 12
0 0
0 1
0 1
0 2
23 2
I want to count of number of distinct rows and the number of disinct element
in the second column and put these counts in a column. SO at the end of the
day I should have:
c(1, 1, 1, 2, 2, 1, 1) for the distinct rows...
Let's suppose my.data is your data frame, "var" is the 1st column and
"var1" is the second.
1) Create a 3rd columns for the first task:
my.data$var2<-0
2) Count distinct rows:
for (i in 1:nrow(my.data)) { my.data$var2[i]<-nrow(subset(my.data,
var==var[i] & var1==var1[i])) }
After this, the output of "my.data$var2" is:
[1] 1 1 1 2 2 1 1
> ... and c(1, 1, 1, 2, 2, 2, 2) for the counts of how many times the
> elements in the second column exists.
Here I'm a bit irritated. Shouldn't the count for the first element "1"
rather be 3, since the number 3 occurs three times... If this is what
You are looking for, then the following should work:
1) Create a 4th column for:
my.data$var3<-0
2) Count distinct elements in the second column:
for (i in 1:nrow(my.data)) {
my.data$var3[i]<-sum(my.data$var1==my.data$var1[i]) }
After this, the output of "my.data$var3" is:
[1] 3 1 1 3 3 2 2
HTH,
Kimmo
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