R consistent integer division and modulo operation#250
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MichaelChirico merged 3 commits intomainfrom Jan 25, 2026
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| 1. `as.integer64.integer64` returns a plain `integer64` vector stripped of any attributes. This is consistent with R like behavior, e.g. `as.integer.integer`. | ||
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| 1. `%/%` does not truncate towards zero any more. It now matches R behavior of truncating towards negative infinity. For example, `as.integer64(-10L) %/% as.integer64(7L)` now gives `-2L`, not `-1L`. This is consistent with `-10L %/% 7L` in base R. Consequently, `%%` is also affected, e.g. `as.integer64(-10L) %% as.integer64(7L)` now gives `4L`, not `-3L`, consistent with `-10L %% 7L` in base R. |
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In ?"%/%" this is described as Knuth's floor() behavior:
x %/% y := floor(x / y)
I think it will be helpful to use that terminology to anchor more definitively to the base rule.
MichaelChirico
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Since the previous behavior is IMO incorrect, I think of this more as a bug, hence less concerned about back-compatibility.
Still, I'll keep an eye on it aroud release time when doing reverse dependency checks -- if it is a recurring source of downstream breaking, we may guard this with a flag, too.
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* r consistent integer division * tweak NEWS --------- Co-authored-by: Michael Chirico <chiricom@google.com>
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* extend c, cbind, and rbind * consistent use of Rboolean (#251) * R consistent integer division and modulo operation (#250) * r consistent integer division * tweak NEWS --------- Co-authored-by: Michael Chirico <chiricom@google.com> * fix test ancient * add origin for as.{Date,POSIXct,POSIXlt} for ancient * `stringsAsFactors=FALSE` for ancient * fix ancient * skip a test for ancient * fix cbind tests for ancient * skip cbind tests for ancient * skip rbind tests for ancient * fix target_class_and_sample_value for missing .bit64.suppressPromoteInteger64ToCharacterMessage * merge target_class_and_sample_value in target_class * touch-ups to c() * touch-ups to rbind,cbind * missing ')' * inherits() instead of class() Co-authored-by: Michael Chirico <chiricom@google.com> * remove eval(str2lang()) * another round of touch-up * vestigial ')' * missing '{' * simplify (?) replacement helper for cbind * more expect_same_error * switch branch order * fix updated logical condition for unnested branches * revert unrelated switch to expect_same_error * replace rbind helper too * fix helper argument name Co-authored-by: Michael Chirico <michaelchirico4@gmail.com> * refactoring, add comments, add news * extract replace_dimnames * tweak NEWS * fix deparse.level problems * skip ancient test * more canonical patrick (avoid expand.grid), don't test 4 * raw cases * missing symmetric cases for difftime, factor, ordered * explicitly ignore coercion warning before error --------- Co-authored-by: Michael Chirico <chiricom@google.com> Co-authored-by: Michael Chirico <michaelchirico4@gmail.com>
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The integer division is changed to meet the behavior of base R for integer. I couldn't find any "option" to change the behaviour for
long long int, so I added logic.Closes #248