| octmode {base} | R Documentation |
Integer Numbers Displayed in Octal
Description
Integers which are displayed in octal (base-8 number system) format, with as many digits as are needed to display the largest, using leading zeroes as necessary.
Arithmetic works as for integers, and non-integer valued mathematical functions typically work by truncating the result to integer.
Usage
as.octmode(x)
## S3 method for class 'octmode'
as.character(x, keepStr = FALSE, ...)
## S3 method for class 'octmode'
format(x, width = NULL, ...)
## S3 method for class 'octmode'
print(x, ...)
Arguments
x |
an object, for the methods inheriting from class |
keepStr |
a |
width |
|
... |
further arguments passed to or from other methods. |
Details
"octmode" objects are integer vectors with that class
attribute, used primarily to ensure that they are printed in octal
notation, specifically for Unix-like file permissions such as
755. Subsetting ([) works too, as do arithmetic or
other mathematical operations, albeit truncated to integer.
as.character(x) drops all attributes (unless when
keepStr=TRUE where it keeps, dim, dimnames and
names for back compatibility) and converts each entry individually, hence with no
leading zeroes, whereas in format(), when width = NULL (the
default), the output is padded with leading zeroes to the smallest width
needed for all the non-missing elements.
as.octmode can convert integers (of type "integer" or
"double") and character vectors whose elements contain only
digits 0-7 (or are NA) to class "octmode".
There is a ! method and methods for | and
&:
these recycle their arguments to the length of the longer and then
apply the operators bitwise to each element.
See Also
These are auxiliary functions for file.info.
hexmode, sprintf for other options in
converting integers to octal, strtoi to convert octal
strings to integers.
Examples
(on <- as.octmode(c(16, 32, 127:129))) # "020" "040" "177" "200" "201"
unclass(on[3:4]) # subsetting
## manipulate file modes
fmode <- as.octmode("170")
(fmode | "644") & "755"
(umask <- Sys.umask()) # depends on platform
c(fmode, "666", "755") & !umask
om <- as.octmode(1:12)
om # print()s via format()
stopifnot(nchar(format(om)) == 2)
om[1:7] # *no* leading zeroes!
stopifnot(format(om[1:7]) == as.character(1:7))
om2 <- as.octmode(c(1:10, 60:70))
om2 # prints via format() -> with 3 octals
stopifnot(nchar(format(om2)) == 3)
as.character(om2) # strings of length 1, 2, 3
## Integer arithmetic (remaining "octmode"):
om^2
om * 64
-om
(fac <- factorial(om)) # !1, !2, !3, !4 .. in hexadecimals
as.integer(fac) # indeed the same as factorial(1:12)