ceiling(x) floor(x) round(x, digits = 0) signif(x, digits = 6) trunc(x) zapsmall(x, digits= .Options$digits)
ceiling takes a single numeric argument x and returns a
numeric vector containing the smallest integers not less than the
corresponding elements of x.
floor takes a single numeric argument x and returns a
numeric vector containing the largest integers not greater than the
corresponding elements of x.
round rounds the values in its first argument to the specified
number of decimal places (default 0).
Note that for rounding off a 5, the IEEE standard is used,
``go to the even digit''.
Therefore round(0.5) is 0 and round(-1.5) is -2.
signif rounds the values in its first argument to the specified
number of significant digits.
trunc takes a single numeric argument x and returns a
numeric vector containing the integers by truncating the values in
x toward 0.
zapsmall determines a digits argument dr for calling
round(x, digits = dr) such that values ``close to zero'' values
are ``zapped'', i.e., treated as 0.
as.integer.round(.5 + -2:4) # IEEE rounding: -2 0 0 2 2 4 4 ( x1 <- seq(-2, 4, by = .5) ) round(x1)#-- IEEE rounding ! x1[trunc(x1) != floor(x1)] x1[round(x1) != floor(x1 + .5)] all(trunc(x1) == as.integer(x1))# TRUE non.int <- ceiling(x1) != floor(x1) all(non.int == (ceiling(x1) != trunc(x1) | trunc(x1) != floor(x1))) # TRUE all((signif(x1, 1) != round(x1,1)) == (non.int & abs(x1)>1)) # TRUE x2 <- pi * 100^(-1:3) round(x2, 3) signif(x2, 3) print (x2 / 1000, digits=4) zapsmall(x2 / 1000, digits=4)