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Format decimal or integer values

Source: R/format_decimal.R
format_decimal.Rd

Convert the elements of a numerical vector to character strings in which the numbers are formatted using decimal notation and delimited for rendering as inline equations in an R Markdown document.

Usage

format_decimal(x, digits = 4, ..., big_mark = NULL, delim = "$")

Arguments

x

Numeric vector to be formatted.

digits

Numeric scalar, decimal places to report, integer between 0 and 20. Zero returns an integer.

...

Not used, force later arguments to be used by name.

big_mark

Character. If not empty, used as mark between every three digits before the decimal point. Applied as the big.mark argument of formatC().

delim

Character vector (length 1 or 2) defining the delimiters for marking up inline math. Possible values include "$" or "\\(", both of which create appropriate left and right delimiters. Alternatively, left and right can be defined explicitly in a character vector of length two, e.g., c("$", "$") or c("\\(", "\\)"). Custom delimiters can be assigned to suit the markup environment. Use argument by name.

Value

A character vector with the following properties:

  • Numbers represented in integer or decimal notation.

  • Elements delimited as inline math markup.

Details

Given a number, a numerical vector, or a numerical column from a data frame, format_decimal() converts the numbers to character strings of the form, "$a$", where a is the number in decimal notation. The user can specify the number of decimal places.

Delimiters for inline math markup can be edited if necessary. If the default argument fails, the "\\(" alternative is available. If using a custom delimiter to suit the markup environment, be sure to escape all special symbols.

See also

Other format_*: format_power(), format_text(), format_units()

Examples

# Digits
x <- c(12300400.1234, 456000)
format_decimal(x, digits = 0)
#> [1] "$12300400$" "$456000$"  
format_decimal(x, digits = 1)
#> [1] "$12300400.1$" "$456000.0$"  
format_decimal(x, digits = 2)
#> [1] "$12300400.12$" "$456000.00$"  

# Big mark
format_decimal(x, 0, big_mark = ",")
#> [1] "$12,300,400$" "$456,000$"   

# Inline math delimiters
x <- c(1.654321, 0.065432)
format_decimal(x)
#> [1] "$1.6543$" "$0.0654$"
format_decimal(x, 3, delim = "$")
#> [1] "$1.654$" "$0.065$"
format_decimal(x, 3, delim = c("$", "$"))
#> [1] "$1.654$" "$0.065$"
format_decimal(x, 3, delim = "\\(")
#> [1] "\\(1.654\\)" "\\(0.065\\)"
format_decimal(x, 3, delim = c("\\(", "\\)"))
#> [1] "\\(1.654\\)" "\\(0.065\\)"

# LaTeX-style display equation delimiters
format_decimal(x, 3, delim = c("\\[", "\\]"))
#> [1] "\\[1.654\\]" "\\[0.065\\]"

# Apply to columns of a data frame (data.table syntax)
DT <- atmos[, .(temp, sound)]
DT[, lapply(.SD, function(x) format_decimal(x, 1))]
#>       temp   sound
#>     <char>  <char>
#> 1: $288.1$ $340.3$
#> 2: $223.2$ $299.5$
#> 3: $216.7$ $295.1$
#> 4: $226.5$ $301.7$
#> 5: $250.3$ $317.2$
#> 6: $270.6$ $329.8$
#> 7: $247.0$ $315.1$
#> 8: $219.6$ $297.1$
#> 9: $198.6$ $282.5$