length.bit: Getting and setting length of bit, bitwhich and ri objects

In bit: A Class for Vectors of 1-Bit Booleans

Description

Query the number of bits in a bit vector or change the number of bits in a bit vector.
Query the number of bits in a bitwhich vector or change the number of bits in a bit vector.

Usage

## S3 method for class 'ri'
length(x)
## S3 method for class 'bit'
length(x)
## S3 method for class 'bitwhich'
length(x)
## S3 replacement method for class 'bit'
length(x) <- value
## S3 replacement method for class 'bitwhich'
length(x) <- value

Arguments

x	a bit, bitwhich or ri object
value	the new number of bits

Details

NOTE that the length does NOT reflect the number of selected (TRUE) bits, it reflects the sum of both, TRUE and FALSE bits. Increasing the length of a bit object will set new bits to FALSE. The behaviour of increasing the length of a bitwhich object is different and depends on the content of the object:

• TRUEall included, new bits are set to TRUE

• positive integerssome included, new bits are set to FALSE

• negative integerssome excluded, new bits are set to TRUE

• FALSEall excluded:, new bits are set to FALSE

Decreasing the length of bit or bitwhich removes any previous information about the status bits above the new length.

Value

the length A bit vector with the new length

Author(s)

Jens Oehlschlägel

See Also

length, sum, poslength, maxindex

Examples

  stopifnot(length(ri(1, 1, 32))==32)

  x <- as.bit(ri(32, 32, 32))
  stopifnot(length(x)==32)
  stopifnot(sum(x)==1)
  length(x) <- 16
  stopifnot(length(x)==16)
  stopifnot(sum(x)==0)
  length(x) <- 32
  stopifnot(length(x)==32)
  stopifnot(sum(x)==0)

  x <- as.bit(ri(1, 1, 32))
  stopifnot(length(x)==32)
  stopifnot(sum(x)==1)
  length(x) <- 16
  stopifnot(length(x)==16)
  stopifnot(sum(x)==1)
  length(x) <- 32
  stopifnot(length(x)==32)
  stopifnot(sum(x)==1)

  x <- as.bitwhich(bit(32))
  stopifnot(length(x)==32)
  stopifnot(sum(x)==0)
  length(x) <- 16
  stopifnot(length(x)==16)
  stopifnot(sum(x)==0)
  length(x) <- 32
  stopifnot(length(x)==32)
  stopifnot(sum(x)==0)

  x <- as.bitwhich(!bit(32))
  stopifnot(length(x)==32)
  stopifnot(sum(x)==32)
  length(x) <- 16
  stopifnot(length(x)==16)
  stopifnot(sum(x)==16)
  length(x) <- 32
  stopifnot(length(x)==32)
  stopifnot(sum(x)==32)

  x <- as.bitwhich(ri(32, 32, 32))
  stopifnot(length(x)==32)
  stopifnot(sum(x)==1)
  length(x) <- 16
  stopifnot(length(x)==16)
  stopifnot(sum(x)==0)
  length(x) <- 32
  stopifnot(length(x)==32)
  stopifnot(sum(x)==0)

  x <- as.bitwhich(ri(2, 32, 32))
  stopifnot(length(x)==32)
  stopifnot(sum(x)==31)
  length(x) <- 16
  stopifnot(length(x)==16)
  stopifnot(sum(x)==15)
  length(x) <- 32
  stopifnot(length(x)==32)
  stopifnot(sum(x)==31)

  x <- as.bitwhich(ri(1, 1, 32))
  stopifnot(length(x)==32)
  stopifnot(sum(x)==1)
  length(x) <- 16
  stopifnot(length(x)==16)
  stopifnot(sum(x)==1)
  length(x) <- 32
  stopifnot(length(x)==32)
  stopifnot(sum(x)==1)

  x <- as.bitwhich(ri(1, 31, 32))
  stopifnot(length(x)==32)
  stopifnot(sum(x)==31)
  message("NOTE the change from 'some excluded' to 'all excluded' here")
  length(x) <- 16
  stopifnot(length(x)==16)
  stopifnot(sum(x)==16)
  length(x) <- 32
  stopifnot(length(x)==32)
  stopifnot(sum(x)==32)

Example output

Attaching package: ‘bit’

The following object is masked from ‘package:base’:

    xor

NOTE the change from 'some excluded' to 'all excluded' here

bit documentation built on May 2, 2019, 4:48 p.m.