Label numbers with SI prefixes (2 kg, 5 mm, etc)

label_number_si() is deprecated because the previous unit didn't actually use SI units, but instead used the so called "short scale". You can now get the same results as before with label_number(scale_cut = cut_short_scale()), or if you want correct SI units, label_number(scale_cut = cut_si("unit")).

Usage

label_number_si(unit = "", accuracy = NULL, scale = 1, suffix = "", ...)

Arguments

unit

Unit of measurement (e.g. "m" for meter, the SI unit of length).

accuracy

A number to round to. Use (e.g.) 0.01 to show 2 decimal places of precision. If NULL, the default, uses a heuristic that should ensure breaks have the minimum number of digits needed to show the difference between adjacent values.

Applied to rescaled data.

scale

A scaling factor: x will be multiplied by scale before formatting. This is useful if the underlying data is already using an SI prefix.

suffix

Additional text to display after the number.

...

Arguments passed on to label_number

prefix

Additional text to display before the number. The suffix is applied to absolute value before style_positive and style_negative are processed so that prefix = "$" will yield (e.g.) -$1 and ($1).

big.mark

Character used between every 3 digits to separate thousands.

decimal.mark

The character to be used to indicate the numeric decimal point.

style_positive

A string that determines the style of positive numbers:

• "none" (the default): no change, e.g. 1.

• "plus": preceded by +, e.g. +1.

• "space": preceded by a Unicode "figure space", i.e., a space equally as wide as a number or +. Compared to "none", adding a figure space can ensure numbers remain properly aligned when they are left- or right-justified.

style_negative

A string that determines the style of negative numbers:

• "hyphen" (the default): preceded by a standard hypen -, e.g. -1.

• "minus", uses a proper Unicode minus symbol. This is a typographical nicety that ensures - aligns with the horizontal bar of the the horizontal bar of +.

• "parens", wrapped in parentheses, e.g. (1).

scale_cut

Named numeric vector that allows you to rescale large (or small) numbers and add a prefix. Built-in helpers include:

• cut_short_scale(): [10^3, 10^6) = K, [10^6, 10^9) = M, [10^9, 10^12) = B, [10^12, Inf) = T.

• cut_long_scale(): [10^3, 10^6) = K, [10^6, 10^12) = M, [10^12, 10^18) = B, [10^18, Inf) = T.

• cut_si(unit): uses standard SI units.

If you supply a vector c(a = 100, b = 1000), absolute values in the range [0, 100) will not be rescaled, absolute values in the range [100, 1000) will be divided by 100 and given the suffix "a", and absolute values in the range [1000, Inf) will be divided by 1000 and given the suffix "b". If the division creates an irrational value (or one with many digits), the cut value below will be tried to see if it improves the look of the final label.

trim

Logical, if FALSE, values are right-justified to a common width (see base::format()).

Value

All label_() functions return a "labelling" function, i.e. a function that takes a vector x and returns a character vector of length(x) giving a label for each input value.

Labelling functions are designed to be used with the labels argument of ggplot2 scales. The examples demonstrate their use with x scales, but they work similarly for all scales, including those that generate legends rather than axes.

See also

Other labels for continuous scales: label_bytes(), label_currency(), label_number_auto(), label_ordinal(), label_parse(), label_percent(), label_pvalue(), label_scientific()

Other labels for log scales: label_bytes(), label_log(), label_scientific()