On Dec 6, 2008, at 11:30 AM, Edwin Sendjaja wrote:
Hi,
I have a table for an 1 week exam result for many classes in school,
like
this:
Day Class_ID Test Result
1 Monday 1 Paper Passed
2 Tuesday 1 Oral Passed
3 Friday 1 Paper Passed
4 Monday 3 Paper Passed
5 Sunday 3 Oral Passed
6 Monday 3 Paper Passed
6 Sunday 3 Paper Passed
How can I sum the Word "Passed" from Result column ( for earch
Class_ID and
each Test), so i can get this following table:
Class_ID Test Passed_Count
1 1 Paper 2
2 1 Oral 1
3 3 Oral 1
4 3 Paper 3
Try
> xtabs( formula= ~ Test + Class_ID, data=cdat)
Class_ID
Test 1 3
Oral 1 1
Paper 2 3
> as.data.frame(xtabs( formula= ~ Test + Class_ID, data=cdat))
Test Class_ID Freq
1 Oral 1 1
2 Paper 1 2
3 Oral 3 1
4 Paper 3 3
This does not really sum the "Passed" column but rather counts the
number of entries (which all happen to be "Passed" in your example
data. (You also offered a data set with duplicate row numbers which
was corrected.) Had you offered a dataset in which Result were
somewhat more interesting, then counting the number of Passed might
have required putting (Result=="Passed") on the left side of the
formula.
--
David Winsemius
Passed_Count column is just the Value, how many people passed the
exam. In the
tabell, they are 2 people passed the paper test (Result=Passed).
I hope someone can help me, Or maybe there is an example that i can
see.
Thank you in advance
______________________________________________
R-help@r-project.org 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.
______________________________________________
R-help@r-project.org 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.
