rows-columns: Apply conditional formatting to cells with 'rows' and...

In rstudio/gt: Easily Create Presentation-Ready Display Tables

Apply conditional formatting to cells with rows and columns

Description

To apply styling or formatting, you can use the columns and rows arguments. The syntax should be very familiar for dplyr users as you can use the tidyselect specification.

Targeting of values is done through columns and additionally by rows (if nothing is provided for rows then entire columns are selected). The columns argument allows us to target a subset of cells contained in the resolved columns. We say resolved because aside from declaring column names in c() (with bare column names or names in quotes) we can use tidyselect-style expressions. This can be as basic as supplying a select helper like starts_with(), or, providing a more complex incantation like

where(~ is.numeric(.x) & max(.x, na.rm = TRUE) > 1E6)

which targets numeric columns that have a maximum value greater than 1,000,000 (excluding any NAs from consideration).

By default all columns and rows are selected (with the everything() defaults). Cell values that are incompatible with a given formatting function will be skipped over, like character values and numeric ⁠fmt_*()⁠ functions. So it's safe to select all columns with a particular formatting function (only those values that can be formatted will be formatted), but, you may not want that. One strategy is to format the bulk of cell values with one formatting function and then constrain the columns for later passes with other types of formatting (the last formatting done to a cell is what you get in the final output).

Once the columns are targeted, we may also target the rows within those columns. This can be done in a variety of ways. If a stub is present, then we potentially have row identifiers. Those can be used much like column names in the columns-targeting scenario. We can use simpler tidyselect-style expressions (the select helpers should work well here) and we can use quoted row identifiers in c(). It's also possible to use row indices (e.g., c(3, 5, 6)) though these index values must correspond to the row numbers of the input data (the indices won't necessarily match those of rearranged rows if row groups are present). One more type of expression is possible, an expression that takes column values (can involve any of the available columns in the table) and returns a logical vector. This is nice if you want to base formatting on values in the column or another column, or, you'd like to use a more complex predicate expression.

Examples

gt_tbl <- gt(exibble)
gt_tbl %>%
  fmt_time(
    columns = contains("time") & !starts_with("date"),
     rows = num > 100 & group == "grp_b"
  )

# Styling numeric columns based on range

gt_tbl %>% tab_style(
  style = cell_text(weight = "bold"),
  locations = cells_body(
  columns =  where(is.factor)
  )
)

# Naming rows

gt_tbl_rows <- gt(exibble, rowname_col = "row")
gt_tbl_rows %>%
  fmt_datetime(
    columns = datetime,
    rows = c("row_1", "row_8")
  )

rstudio/gt documentation built on Dec. 2, 2024, 11:05 a.m.