R: Integer Numbers Displayed in Octal

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 `"octmode"`.
`keepStr`	a `logical` indicating that names and dimensions should be kept; set `TRUE` for back compatibility, if needed.
`width`	`NULL` or a positive integer specifying the minimum field width to be used, with padding by leading zeroes.
`...`	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.

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)