key argument for as.data.table methods

[MichaelChirico]

Closes #890

@jangorecki thanks for the heads up that this never ended up merged (3 years ago!)

Requesting review since there's a potentially breaking change to as.data.table.array -- key argument has to be brought to the front (S3 method consistency), so anyone that's relying on the ordering of the arguments to as.data.table.array will be affected by this PR.

PS Jan, could you please change the manual entry for the sorted argument to as.data.table.array? It gives no information about what it's used for, just that it's passed to the method.

[codecov]

Codecov Report

Merging #3573 into master will increase coverage by 0.03%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #3573      +/-   ##
==========================================
+ Coverage   97.58%   97.62%   +0.03%     
==========================================
  Files          66       66              
  Lines       12695    12698       +3     
==========================================
+ Hits        12389    12397       +8     
+ Misses        306      301       -5

Impacted Files	Coverage Δ
R/xts.R	100% <100%> (ø)	⬆️
R/as.data.table.R	99.15% <100%> (+4.24%)	⬆️

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[MichaelChirico]

@jangorecki ok done

[jangorecki]

Looks like https://codecov.io/gh/Rdatatable/data.table/compare/c68e95ec5860a947092be8c3fbfadd8f657ebf72...36e137b0b95175464746ad252a6800f40f8c5fe9/src/R/as.data.table.R#L155 cannot be covered. Unnamed list doesn't hit that branch, maybe safe to remove?

[MichaelChirico]

Not quite, I missed it. Adding a test now.

[MichaelChirico]

NVM, @jangorecki was right (though my test indeed was not working as intended), that line is un-hittable. mn > 0 case will cover naming for all normal inputs; even if mn == 0, setDT handles the naming.