| Round {base} | R Documentation |
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.
trunc takes a single numeric argument x and returns a
numeric vector containing the integers formed by truncating the values in
x toward 0.
round rounds the values in its first argument to the specified
number of decimal places (default 0).
signif rounds the values in its first argument to the specified
number of significant digits.
zapsmall determines a digits argument dr for
calling round(x, digits = dr) such that values “close to
zero” (compared with the maximal absolute value) are “zapped”,
i.e., treated as 0.
ceiling(x)
floor(x)
trunc(x)
round(x, digits = 0)
signif(x, digits = 6)
zapsmall(x, digits = getOption("digits"))
x |
a numeric vector. A complex vector is allowed for
round, signif and zapsmall. |
digits |
integer indicating the precision to be used. |
All but zapsmall are generic functions: methods can be
defined for them individually or via the Math group generic.
Note that for rounding off a 5, the IEC 60559 standard is used,
“go to the even digit”.
Therefore round(0.5) is 0 and round(-1.5) is -2.
For signif the recognized values of digits are
1...22. As from R 2.2.0 complex numbers are rounded to retain
the specified number of digits in the larger of the components. Each
element of the vector is rounded individually, unlike printing.
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)
The New S Language.
Wadsworth & Brooks/Cole. (Except zapsmall.)
Chambers, J. M. (1998)
Programming with Data. A Guide to the S Language.
Springer. (zapsmall.)
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)] (non.int <- ceiling(x1) != floor(x1)) x2 <- pi * 100^(-1:3) round(x2, 3) signif(x2, 3) print (x2 / 1000, digits=4) zapsmall(x2 / 1000, digits=4) zapsmall(exp(1i*0:4*pi/2))