gdata (version 2.16.1)

humanReadable: Print Byte Size in Human Readable Format

Description

humanReadable converts integer byte sizes to a human readable units such as kB, MB, GB, etc.

Usage

humanReadable(x, units="auto", standard=c("IEC", "SI", "Unix"),
              digits=1, width=NULL, sep=" ", justify=c("right", "left") )

Arguments

x

integer, byte size

standard

character, "IEC" for powers of 1024 ('MiB'), "SI" for powers of 1000 ('MB'), or "Unix" for powers of 1024 ('M'). See details.

units

character, unit to use for all values (optional), one of "auto", "bytes", or an appropriate unit corresponding to standard.

digits

integer, number of digits after decimal point

width

integer, width of number string

sep

character, separator between number and unit

justify

two-element vector specifiy the alignment for the number and unit components of the size. Each element should be one of "none", "left", "right", or "center"

Value

• Byte size in human readable format as character with proper unit symbols added at the end of the string.

Details

The basic unit used to store information in computers is a bit. Bits are represented as zeroes and ones - binary number system. Although, the binary number system is not the same as the decimal number system, decimal prefixes for binary multiples such as kilo and mega are often used. In the decimal system kilo represent 1000, which is close to $1024 = 2^{10}$ in the binary system. This sometimes causes problems as it is not clear which powers (2 or 10) are used in a notation like 1 kB. To overcome this problem International Electrotechnical Commission (IEC) has provided the following solution to this problem:

lrcll{ Name System Symbol Size Conversion byte binary B $2^3$ 8 bits kilobyte decimal kB $10^3$ 1000 bytes kibibyte binary KiB $2^{10}$ 1024 bytes megabyte decimal MB $(10^3)^2$ 1000 kilobytes mebibyte binary MiB $(2^{10})^2$ 1024 kibibytes gigabyte decimal GB $(10^3)^3$ 1000 megabytes gibibyte binary GiB $(2^{10})^3$ 1024 mebibytes terabyte decimal TB $(10^3)^4$ 1000 gigabytes tebibyte binary TiB $(2^{10})^4$ 1024 gibibytes petabyte decimal PB $(10^3)^5$ 1000 terabytes pebibyte binary PiB $(2^{10})^5$ 1024 tebibytes exabyte decimal EB $(10^3)^6$ 1000 petabytes exbibyte binary EiB $(2^{10})^6$ 1024 pebibytes zettabyte decimal ZB $(10^3)^7$ 1000 exabytes zebibyte binary ZiB $(2^{10})^7$ 1024 exbibytes yottabyte decimal YB $(10^3)^8$ 1000 zettabytes yebibyte binary YiB $(2^{10})^8$ 1024 zebibytes }

where Zi and Yi are GNU extensions to IEC. To get the output in the decimal system (powers of 1000) use standard="SI". To obtain IEC standard (powers of 1024) use standard="IEC".

In addition, single-character units are provided that follow (and extend) the Unix pattern (use standard="Unix"):

lrcll{ Name System Symbol Size Conversion byte binary B $2^3$ 8 bits kibibyte binary K $2^{10}$ 1024 bytes mebibyte binary M $(2^{10})^2$ 1024 kibibytes gibibyte binary G $(2^{10})^3$ 1024 mebibytes tebibyte binary T $(2^{10})^4$ 1024 gibibytes pebibyte binary P $(2^{10})^5$ 1024 tebibytes exbibyte binary E $(2^{10})^6$ 1024 pebibytes zebibyte binary Z $(2^{10})^7$ 1024 exbibytes yottabyte binary Y $(2^{10})^8$ 1024 zebibytes }

For printout both digits and width can be specified. If width is NULL, all values have given number of digits. If width is not NULL, output is rounded to a given width and formated similar to human readable format of the Unix ls, df or du shell commands.

References

Wikipedia: http://en.wikipedia.org/wiki/Byte http://en.wikipedia.org/wiki/SI_prefix http://en.wikipedia.org/wiki/Binary_prefix

GNU manual for coreutils: http://www.gnu.org/software/coreutils/manual/html_node/Block-size.html#Block-size

See Also

object.size in package 'gdata', object.size in package 'utils', ll

Examples

# Simple example: maximum addressible size of 32 bit pointer
humanReadable(2^32-1)
humanReadable(2^32-1, standard="IEC")
humanReadable(2^32-1, standard="SI")
humanReadable(2^32-1, standard="Unix")

humanReadable(2^32-1, unit="MiB")
humanReadable(2^32-1, standard="IEC",  unit="MiB")
humanReadable(2^32-1, standard="SI",   unit="MB")
humanReadable(2^32-1, standard="Unix", unit="M")

# Vector of sizes
matrix(humanReadable(c(60810, 124141, 124, 13412513), width=4))
matrix(humanReadable(c(60810, 124141, 124, 13412513), width=4, unit="KiB"))

# Specify digits rather than width
matrix(humanReadable(c(60810, 124141, 124, 13412513), width=NULL, digits=2))

# Change the justification
matrix(humanReadable(c(60810, 124141, 124, 13412513), width=NULL,
                    justify=c("right", "right") ))