[datatable-help] [J(channel) , ] [J(chan) , ] give different results when chan=channel

[Dieter Menne]

I just got bitten by a nasty bug in my code:


library(data.table)
eso = data.table(pH=rnorm(10),channel=1:2,key="channel")
chan = 1
channel = chan

eso[J(chan)]    # not a column name, returns what I want
eso[J(channel)] # channel is a column and key, returns all

>From a standpoint of evaluation, it is clear to me what happens, but I find
this behavior highly confusing. I would wish if the latter could optionally
be flagged with a warning, in case this is not "by design".

Dieter





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