I had expected rbindlist() to preserve attributes, but it doesn't. It'd be a nice feature; or an important limitation to disclose in the documentation.

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Assessment

Difficulty
5/5
Estimated time
Over a week
Newbie friendliness
30/100
Issue type
Feature
Clarity
Mostly clear
Activity status
Stale
Tech stack
r
Domain
data-engineering

Research direction

Start by reproducing the example with data.table::rbindlist() and inspect the resulting attributes. Determine how attributes such as xa and ya should be handled when inputs differ; done means either preserving the agreed attributes or documenting the limitation clearly.

Written by the indexing model from the issue text.

Description

[rbind|cbind|merge]list feature request

# Minimal reproducible example

library(data.table)
x <- data.table(0)
setattr(x,"xa",0)
y <- data.table(1)
setattr(y,"ya",1)
z <- rbindlist(list(x,y))
attributes(z)
#> $names
#> [1] "V1"
#> 
#> $row.names
#> [1] 1 2
#> 
#> $class
#> [1] "data.table" "data.frame"
#> 
#> $.internal.selfref
#> <pointer: 0x00000239858df980>
# I had expected attributes(z) to include at least "xa", or both "xa" and "ya".

Created on 2022-12-20 with reprex v2.0.2

# Output of sessionInfo()

sessionInfo()
#> R version 4.2.2 (2022-10-31 ucrt)
#> Platform: x86_64-w64-mingw32/x64 (64-bit)
#> Running under: Windows 10 x64 (build 22621)
#> 
#> Matrix products: default
#> 
#> locale:
#> [1] LC_COLLATE=English_New Zealand.utf8  LC_CTYPE=English_New Zealand.utf8   
#> [3] LC_MONETARY=English_New Zealand.utf8 LC_NUMERIC=C                        
#> [5] LC_TIME=English_New Zealand.utf8    
#> 
#> attached base packages:
#> [1] stats     graphics  grDevices utils     datasets  methods   base     
#> 
#> loaded via a namespace (and not attached):
#>  [1] rstudioapi_0.14   knitr_1.41        magrittr_2.0.3    R.cache_0.16.0   
#>  [5] rlang_1.0.6       fastmap_1.1.0     stringr_1.5.0     styler_1.8.1     
#>  [9] highr_0.9         tools_4.2.2       xfun_0.34         R.oo_1.25.0      
#> [13] cli_3.4.1         withr_2.5.0       htmltools_0.5.3   yaml_2.3.6       
#> [17] digest_0.6.29     lifecycle_1.0.3   purrr_0.3.5       vctrs_0.5.0      
#> [21] R.utils_2.12.2    fs_1.5.2          glue_1.6.2        evaluate_0.18    
#> [25] rmarkdown_2.18    reprex_2.0.2      stringi_1.7.8     compiler_4.2.2   
#> [29] R.methodsS3_1.8.2

Created on 2022-12-20 with reprex v2.0.2

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