Extend ..var to work in some other cases
Nobody has claimed this yet.
Assessment
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Newbie friendliness
- 35/100
Research direction
The issue gives f2 and f3 as the target cases; start by reproducing both in data.table and tracing the existing ..var lookup rules. Define which syntax should be supported, then verify the selected behavior for both equality filtering and on=.(v) joins.
Written by the indexing model from the issue text.
Description
I have a column named v and want to filter my table by equality testing that column against a particular value, which I also call v (passing it via a function):
library(data.table)
L = list(A = list(B = list(CDT = data.table(v = c("bah", "egad")))))
# my current function
f = function(v){
v0 = v
myCDT = L$A$B$CDT[v == v0]
# ... do other stuff ...
}
f("bah")[]
# v
# 1: bah
I'd like to retain my preferred naming pattern without fiddling with the assignment to v0:
# what I'd like to write
f2 = function(v){
myCDT = L$A$B$CDT[.(..v), on=.(v)]
# ...
}
# or
f3 = function(v){
myCDT = L$A$B$CDT[v == ..v]
# ...
}
Neither of these works right now because ..var is only checked when j matches it (is my understanding),. But it would be nice to have... that or some other simple way of disambiguating in cases like this.
- Dominant language
- R
- Stars
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- Merged PRs (30d)
- 4
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