Question

I have a dataframe that looks like this:

step  var1  score1  score2
1      a    0        0
2      b    1        1
3      d    1        1
4      e    0        0
5      g    0        0
1      b    1        1
2      a    1        0
3      d    1        0
4      e    0        1
5      f    1        1
1      g    0        1
2      d    1        1
etc.

Because I need to correlate variabeles a-g (their scores are in score1) with score2 in only step 5 I think i need to schange my dataset into this first:

a   b   c   d   e   f   g   score2_step5
0   1       1   0       0   0
1   1       1   0   1       1
            1           0 
etc.

I am pretty sure that the Reshape package should be able to help me to do the job, but I haven’t been able to make it work yet.
Can anyone help me? Many thanks in advance!

Answer 1

Here’s another version. In case there is no step = 5, the value for score2_step = 0. Assuming your data.frame is df:

require(reshape2)
out <- do.call(rbind, lapply(seq(1, nrow(df), by=5), function(ix) {
    iy <- min(ix+4, nrow(df))
    df.b <- df[ix:iy, ]
    tt <- dcast(df.b, 1 ~ var1, fill = 0, value.var = "score1", drop=F)
    tt$score2_step5 <- 0
    if (any(df.b$step == 5)) {
        tt$score2_step5 <- df.b$score2[df.b$step == 5]
    }
    tt[,-1]
}))

> out
   a b d e f g score2_step5
2  0 1 1 0 0 0            0
21 1 1 1 0 1 0            1
22 0 0 1 0 0 0            0