Expand is a complement to the base R rounding functions, particularly trunc.
Details
Each of the four base R functions---round, ceiling, floor, and trunc---follow
a different logic in how they round real numbers to ingegers:
round: round to nearest integer in either direction.floor: round downward towards negative infinity.Negative numbers are rounded to "more negative" numbers.
ceiling: round upward towards infinity.Negative numbers are rounded to "less negative" numbers.
trunc: round "inward" towards zero.Negative numbers are rounded up to "less negative" numbers, but positive numbers are still rounded downwards to "less positive" numbers.
Just as ceiling compliments floor, the humdrumR function expand acts
as a compliment to trunc: expand rounds "outward" away from zero.
Negative numbers are rounded to "more negative" numbers and positive numbers
are rounded to "more positive" numbers.
A table explains better than words:
| Call | Returns |
round(c(2.9, 3.1, -2.9, -3.1)) | c(3, 3, -3, -3) |
floor(c(2.9, 3.1, -2.9, -3.1)) | c(2, 3, -3, -4) |
ceiling(c(2.9, 3.1, -2.9, -3.1)) | c(3, 4, -2, -3) |
trunc(c(2.9, 3.1, -2.9, -3.1)) | c(2, 3, -2, -3) |
expand(c(2.9, 3.1, -2.9, -3.1)) | c(3, 4, -3, -4) |