Reshape in R without aggregation (for example MTurk response strings)

Question

Ordinarily, I\'d use a pretty basic long-to-wide reshape for this, but it seems to be dropping my aggregation variables. The setup is I had a job on mechanical Turk that I perfo

Answer 1

From data.table v1.9.5+, dcast can handle multiple value.var columns, i.e., we can cast multiple columns simultaneously. We can simply do:

dt[, id := seq_len(.N), by=Input.id]
dcast(dt, Input.id + Input.State ~ id, 
        value.var=c("AssignmentStatus", "Answer.Q1thing"))
#    Input.id Input.State 1_AssignmentStatus 2_AssignmentStatus 3_AssignmentStatus
# 1:   134231          NY           Approved           Approved           Approved
# 2:   134812          CA          Submitted           Approved           Approved
#    1_Answer.Q1thing 2_Answer.Q1thing 3_Answer.Q1thing
# 1:          Myguess          Myguess         BadGuess
# 2:          Another          Another          Another

Or everything together in one line:

dcast(dt, Input.id + Input.State ~ dt[, seq_len(.N), by=Input.id]$V1, 
                 value.var=c("AssignmentStatus", "Answer.Q1thing"))