mapping-functions {huxtable}

How to set cell properties variably by cell contents

Description

This help page explains how to set properties differently for cells, depending on their contents.

For example, in a table of p-values, you could bold cells where p < 0.05:

  map_bold(pval_hux, by_ranges(0.05, c(TRUE, FALSE)))

Or you can use red text for a particular value:

  hxtbl %>% map_text_color(by_values("Warning" = "red"))

There is a map_... function for each huxtable cell property. The syntax is:

  map_property(ht, row, col, fn)

where property is the property name.

row and col specify ranges of rows and columns. See rowspecs for details. To set properties for the whole table, omit row and col:

  map_property(ht, fn)

The fn argument is a mapping function which maps cell contents to property values.

• To set property values in "stripes" by rows or by columns, use by_rows() and by_cols().

• To set property values for cells with specific contents, use by_values().

• To set property values for cells within a numeric range, use by_ranges().

• To set property values for cells by quantiles, use by_quantiles() or by_equal_groups().

• To set property values for cells that match a string or regular expression, use by_regex().

• To map numeric values to a colorspace, use by_colorspace().

• For a more general solution, use by_function() or by_cases().

Caveat

Most functions convert the huxtable to a matrix using as.matrix(). This can have unexpected results if you mix character and numeric data. See the example.

Technical details

fn takes four arguments: the entire original huxtable ht, a numeric vector of rows, a numeric vector of cols, and the current property values for ht[rows, cols], as a matrix. It should return the new property values for ht[rows, cols], as a matrix.

Examples

ht <- hux(Condition = c("OK", "Warning", "Error"))
ht <- map_text_color(ht, by_values(
        OK      = "green",
        Warning = "orange",
        Error   = "red"
      ))
ht

# Leaving NA values alone:
map_text_color(ht, by_values(
      "OK" = "blue", NA, ignore_na = TRUE))

# Resetting values:
map_text_color(ht, by_values(
      "OK" = "blue", NA, ignore_na = FALSE))

ht <- as_hux(matrix(rnorm(15), 5, 3))
map_background_color(ht, by_ranges(
        c(-1, 1),
        c("blue", "yellow", "red")
      ))
map_background_color(ht,
      by_equal_groups(2, c("red", "green")))

ht <- hux(
        Coef = c(3.5, 2.4, 1.3),
        Pval = c(0.04, 0.01, 0.07),
        add_colnames = TRUE
      )
map_bold(ht, everywhere, "Pval",
      by_ranges(0.05, c(TRUE, FALSE)))

# Problems with as.matrix:

ht <- hux(c(-1, 1, 2), letters[1:3])
as.matrix(ht)          # look at the spaces...
as.matrix(ht) > 0      # uh oh
map_text_color(ht,
      by_cases(. < 0 ~ "red", TRUE ~ "blue"))

# To avoid this, only look at the truly numeric columns:
map_text_color(ht, row = 1:3, col = 1,
      by_cases(. < 0 ~ "red", TRUE ~ "blue"))