[R] error: no such index at level 2

[Godmar Back]

Hi,

I am confused about how to select elements from a list.

I'm trying to select all rows of a table 'crossRsorted' such that the
mean of a related vector is > 0.  The related vector is accessible as
a list element l[[i]] where i is the row index.

I thought this would work:

> crossRsorted[mean(q[[ crossRsorted[,1] ]], na.rm = TRUE) > 0, ]
Error in q[[crossRsorted[, 1]]] : no such index at level 2

How can I express: "select only those rows 'r_i' from crossRsorted
where mean(q[[r_i[1]]]) > 0?

Thanks,

 - Godmar