format_engr {formatdown}

Format engineering notation

Description

Convert a numeric vector to a character vector in which the numbers are formatted in power-of-ten notation in engineering form and delimited for rendering as inline equations in an R markdown document.

Usage

format_engr(
  x,
  digits = 4,
  ...,
  omit_power = c(-1, 2),
  set_power = NULL,
  delim = formatdown_options("delim"),
  size = formatdown_options("size"),
  decimal_mark = formatdown_options("decimal_mark"),
  small_mark = formatdown_options("small_mark"),
  small_interval = formatdown_options("small_interval"),
  whitespace = formatdown_options("whitespace")
)

Arguments

x

Number or numbers to be formatted. Can be a single number, a vector, or a column of a data frame.

digits

Integer from 1 through 20 that controls the number of significant digits in printed numeric values. Passed to signif(). Default is 4.

...

Not used for values; forces subsequent arguments to be referable only by name.

omit_power

Numeric vector c(p, q) with p <= q, specifying the range of exponents over which power-of-ten notation is omitted in either scientific or engineering format. Default is c(-1, 2). If a single value is assigned, i.e., omit_power = p, the argument is interpreted as c(p, p). If NULL or NA, all elements are formatted in power-of-ten notation. Argument is overridden by specifying set_power or decimal notation.

set_power

Integer, length 1. Formats all values in x with the same power-of-ten exponent. Default NULL. Overrides format and omit_power arguments.

delim

Character, length 1 or 2, to define the left and right math markup delimiters. The default setting, delim = "$", produces left and right delimiters ⁠$...$⁠. The alternate built-in setting, delim = "\(", produces left and right delimiters ⁠\\( ... \\)⁠. Custom delimiters can be assigned in a vector of length 2 with left and right delimiter symbols, e.g., ⁠c("\\[", "\\]")⁠. Special characters typically must be escaped.

size

Character, length 1, to assign a font size. If not empty, adds a font size macro to the markup inside the math delimiters. Possible values are "scriptsize", "small", "normalsize", "large", and "huge". One may also assign the equivalent LaTeX-style markup itself, e.g., "\\scriptsize", "\\small", etc. Default is NULL.

decimal_mark

Character, length 1, to assign the decimal marker. Possible values are a period "." (default) or a comma ",". Passed to formatC(decimal.mark).

small_mark

Character, length 1, used as the mark between every small_interval number of digits to the right of the decimal marker to improve readability. Possible values are empty "" (default) or "thin" to produce a LaTeX-style thin, horizontal space. One may also assign the thin-space markup itself "\\\\,". Passed to formatC(small.mark).

small_interval

Integer, length 1, that defines the number of digits (default 5) in groups separated by small_mark. Passed to formatC(small.interval).

whitespace

Character, length 1, to define the LaTeX-style math-mode macro to preserve a horizontal space between words of text or between physical-unit abbreviations when formatting numbers of class "units". Default is "\\\\>". Alternatives include "\\\\:" or "⁠\\\\ ⁠".

Details

In engineering notation, all exponents are multiples of three. format_engr() is a wrapper for the more general function format_numbers(). Where defaults are defined by formatdown_options(), users may reassign the arguments locally in the function call or globally using formatdown_options().

Arguments after the dots (...) must be referred to by name.

Value

A character vector in which numbers are formatted in power-of-ten notation in engineering form and delimited for rendering as inline equations in an R markdown document.

See Also

Other format_*: format_dcml(), format_numbers(), format_sci(), format_text()

Examples

# input: single number
x <- 6.0221E+23
format_numbers(x)

# input: units class
x <- 103400
units(x) <- "N m2 C-2"
format_numbers(x)

# input: vector
data("metals", package = "formatdown")
x <- metals$dens
format_numbers(x)

# significant digits
x <- 9.75358e+5
format_numbers(x, 2)
format_numbers(x, 3)
format_numbers(x, 4)

# format & wrappers: format_engr(), format_sci(), format_dcml()
x <- 6.0221E+23
format_numbers(x, format = "engr")
format_engr(x)

format_numbers(x, format = "sci")
format_sci(x)

x <- 103400
format_numbers(x, format = "dcml")
format_dcml(x)

# input: data frame
x <- metals[, c("thrm_exp", "thrm_cond")]
as.data.frame(apply(x, 2, format_sci, digits = 3))

# omit_power
x <- 103400
format_sci(x, omit_power = c(-1, 2)) # default
format_sci(x, omit_power = c(-1, 5))
format_sci(x, omit_power = 5) # equivalent to omit_power = c(5, 5)
x <- 1.2
format_sci(x, omit_power = NULL)

# set_power
format_sci(x, set_power = NULL) # default
format_sci(x, set_power = 3)

# set_power overrides format
x <- 6.0221E+23
format_engr(x)
format_engr(x, set_power = 24L)
format_sci(x)
format_sci(x, set_power = 24L)

# set_power overrides omit_power
x <- 101300
format_sci(x, omit_power = 5)
format_sci(x, omit_power = 5, set_power = 2)
format_sci(x, omit_power = 2)
format_sci(x, omit_power = 2, set_power = 2)

# decimal format ignores set_power
x <- 103400
format_numbers(x, format = "dcml")
format_numbers(x, format = "dcml", set_power = 3)