col//label is a way to select the column name in the data set to use for plotting as well as the label to use for the axis in the plot. This is a simple data structure that pmplots parses and uses under the hood. Don’t worry about calling col_label() yourself; we’ll just use it here to illustrate.

If we want to use weight from the data set and give it a nice name, we can use the col//label format

x <- "WT // Weight (kg)"

Here, we’ve put the column name to the left of // and the axis label name to the right. pmplots will parse it like this

## [1] "WT"          "Weight (kg)"

and use the first item to select data from the data frame and the second to label your plot.

If you are making a simple plot and don’t want to add an additional label, pmplots will just use the column name as the axis label.

col_label("WT")
## [1] "WT" "WT"

You can use alternative separators

col_label("WT @@ Weight")
## [1] "WT"     "Weight"

You can also include TeX code in the label part which can be utilized in certain plots

col_label("DV // Concentration ($\\mu$g/mL)")
## [1] "DV"                         "Concentration ($\\mu$g/mL)"

Note: you need the latex2exp package installed to make this work.

In the plot it would look like

dv_pred(pmplots_data_obs(), yname = "Concentration ($\\mu$g/mL)")
## Loading required namespace: latex2exp
## `geom_smooth()` using formula = 'y ~ x'