Compare a variable by group

x_by() (and its infix alias %by%) creates an x_by Variable Mapper that reads as "compare x by group". Expressions are captured unevaluated, similar to how ggplot2::aes() captures aesthetics.

Usage

x_by(x, group)

x %by% group

Arguments

x

The response variable. Accepts a bare name, a c() of bare names, a tidyselect helper (requires data in define_model()), or I(expr) for inline data.

group

The grouping variable. Same rules as x.

Value

An x_by / var_id S7 object.

Examples

# Bare names — resolved later from the data or environment
x_by(extra, group)
#> -- Model Definition ------------------------------------------------------------ 
#> 
#> Variable Mapper : x_by 
#> Args : extra | group 

# Infix alias: identical to x_by(extra, group)
extra %by% group
#> -- Model Definition ------------------------------------------------------------ 
#> 
#> Variable Mapper : x_by 
#> Args : extra | group 

# Inline data via I()
x_by(I(rnorm(30)), I(rep(c("a", "b"), each = 15)))
#> -- Model Definition ------------------------------------------------------------ 
#> 
#> Variable Mapper : x_by 
#> Args : <inline> | <inline> 

# Named inline data
x_by(I(score = rnorm(30)), I(grp = rep(c("a", "b"), each = 15)))
#> -- Model Definition ------------------------------------------------------------ 
#> 
#> Variable Mapper : x_by 
#> Args : <inline> | <inline>