i did this last week as: `dt = subset(dt, select=-c(cytokines, lipids))` which I thought was reasonably elegant but the `subset` help page has this scary warning:

> This is a convenience function intended for use interactively. For programming it is better to use the standard subsetting functions like [, and in particular the non-standard evaluation of argument subset can have unanticipated consequences.

but what the fuck does that mean, and does it matter for this operation?