fcase drops dim attribute

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#6,574 2 comments 0 reactions 0 assignees View on GitHub

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Assessment

Difficulty
3/5
Estimated time
1-2 days
Newbie friendliness
45/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
r
Domain
data

Research direction

Start with the fcase behavior shown in the reproducible example using an xts object, and inspect how its class and attributes are preserved. Verify the result for zoo and xts inputs, then confirm that fcase either retains a one-column matrix or returns a classless vector rather than a non-matrix xts object.

Written by the indexing model from the issue text.

Description

non-atomic column

thank you for the fix to #6480. it mostly works great, but has introduced a weird scenario, where the result thinks its an xts object, but is not a matrix. as xts is an indexed matrix, this should never happen, and the result is now breaking subsequent code. this issue really applies to all zoo objects, not just xts

if fcase kept the ouput as a 1 column matrix, matching what was passed in, this works would be fine (suspect this may break other code)
if fcase returned a vector stripping the class and attributes, this would also be usable
returning this hybrid output (non matrix xts) is problematic

cc @joshuaulrich

MRE:
library(xts)
d <- xts(matrix(runif(4000, 0, 100), ncol = 4), order.by = Sys.Date() + (1:1000))
r <- data.table::fcase(d[,1] > d[,4], d[,2], default = (d[,2] + d[,3]) / 2)
class(r)
#[1] "xts" "zoo"
is.matrix(r)
#[1] FALSE

#data.table_1.16.2

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