Displaying 1 result from an estimated 1 matches for "student_unique_id".
2009 Feb 27
3
Making tapply code more efficient
...variables), but R was spinning for days on my Ubuntu machine
and ultimately I saw a message that R was "killed".
The data I am working with has 800967 total rows and 31 total columns.
The ID variable I use as the index variable in tapply() has 326397
unique cases.
> length(unique(qq$student_unique_id))
[1] 326397
To give a sense of what my data look like and the actual problem,
consider the following:
qq <- data.frame(student_unique_id = factor(c(1,1,2,2,2)),
teacher_unique_id = factor(c(10,10,20,20,25)))
This is a student achievement database where students occupy multiple
rows in the da...