I currently have a data frame whose rows correspond to each student and whose columns are different variables for the student, as shown below:
Lastname Firstname CATALOG_NBR Email StudentID EMPLID Start 1 alastname afirstname 1213 *...@uark.edu 10295236 # 12/2/2008 2 anotherlastname anotherfirstname 1213 *...@uark.edu ## 10295236 9/3/2008 Xattempts Q1 Q2 Q3 Q4 Q5 Q6 Q7 Q8 Q9 Q10 Q11 Q12 Q13 Q14 Q15 Q16 Q17 Q18 Q19 1 1 1 1 0 0 0 0 0 0 0 1 0 0 1 1 0 1 1 0 1 2 1 1 1 1 1 1 0 1 0 0 1 1 0 0 1 0 0 0 0 1 Q20 Q21 Q22 Q23 Q24 Q25 Q26 Q27 Q28 Q29 Q30 Q31 Q32 Score Form CRSE_GRADE_OFF 1 0 0 0 0 0 0 0 0 0 1 0 0 0 9 E D 2 0 0 0 0 0 0 0 0 0 0 1 1 0 13 G D Each student took a pre- and post- test indicated by the date under "Start", column 7. (a date, mm/dd/yyyy, whose mm is 08 or 09 is pre-test; a date whose mm is 11 or 12 is post-test. This test was one of four forms, E, F, G, or H, listed under "Form", column 42. Each test had 32 questions, Q1 to Q32, with a binary 1 indicating the student answered correctly to this question and 0 if incorrectly. I am needing a matrix, y, with five columns labeled: response, i, j, r, s. Column 1 indicates the response (0 or 1) for i-th student, on the j-th question (1:32), on the r-th form (E,F,G,H- these could be changed to numeric 1 for E, 2 for F, etc.), on the s-th test (pre or post indicated by a binary 0 for pre, 1 for post). The data-set is very lengthy of approximately 2000 rows. An efficient way to transform this data into the desired matrix would be very helpful. Thank you. ______________________________________________ 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.
