RoundTo {DescTools}

Round to Multiple

Description

Returns a number rounded to the nearest specified multiple.

Usage

RoundTo(x, multiple = 1, FUN = round)

Arguments

x

numeric. The value to round.

multiple

numeric. The multiple to which the number is to be rounded. Default is 1.

FUN

the rounding function as character or as expression. Can be one out of trunc, ceiling, round (default) or floor.

Details

There are several functions to convert to integers. round rounds to the nearest integer or to any number of digits. Using a negative number rounds to a power of ten, so that round (x, -3) rounds to thousands. Each of trunc, floor and ceiling round in a fixed direction, towards zero, down and up respectively. round is documented to round to even, so round(2.5) is 2.

RoundTo uses round(x/multiple)*multiple to get the result. So if x is equally close to two multiples, the multiple with the smaller absolute value will be returned when round(x/multiple) is even (and the greater when it's odd).
If FUN is set to ceiling it will always round up, and if set to floor it will always round down. See examples for comparison).

Value

the rounded value

Author(s)

Andri Signorell <[e-mail]>

See Also

round, trunc, ceiling, floor

Examples

RoundTo(10, 3)     # Rounds 10 to a nearest multiple of 3 (9)
RoundTo(-10, -3)   # Rounds -10 to a nearest multiple of -3 (-9)

RoundTo(1.3, 0.2)  # Rounds 1.3 to a nearest multiple of 0.2 (1.2)
RoundTo(-1.3, 0.2) # Rounds -1.3 to a nearest multiple of 0.2 (-1.2)
RoundTo(5, -2)     # Returns an error, because -2 and 5 have different signs

# Round down
RoundTo(c(1,-1) * 1.2335, 0.05, floor)
RoundTo(c(1,-1) * 1233.5, 100, floor)

# Round up
RoundTo(c(1,-1) * 1.2335, 0.05, ceiling)
RoundTo(c(1,-1) * 1233.5, 100, ceiling)

# Round towards zero
RoundTo(c(1,-1) * 1.2335, 0.05, trunc)
RoundTo(c(1,-1) * 1233.5, 100, trunc)


x <- c(-1.5,-1.3, 1.3, 1.5)
cbind(x =       x,
      round =   RoundTo(x, 0.2, FUN=round),
      trunc =   RoundTo(x, 0.2, FUN=trunc),
      ceiling = RoundTo(x, 0.2, FUN=ceiling),
      floor =   RoundTo(x, 0.2, FUN=floor)
)

x <- -10:10
cbind(x =       x,
      round =   RoundTo(x, 2, FUN=round),
      trunc =   RoundTo(x, 2, FUN=trunc),
      ceiling = RoundTo(x, 2, FUN=ceiling),
      floor =   RoundTo(x, 2, FUN=floor)
)