Add zero/value columns based on equality conditions

For each pair (condition_names[i], new_cols_names[i]) the function adds a new column to data initialised to 0. Where the row matches data[[condition_var]] == condition_names[i], the new column is set to the value of data[[values_var]] (evaluated as an expression - see Details).

Usage

create_find_columns(
  data,
  condition_names,
  new_cols_names,
  condition_var,
  values_var
)

Arguments

data

A data.frame or data.table.

condition_names

Character vector of values to match against condition_var.

new_cols_names

Character vector with the names of the new columns to create. Same length as condition_names.

condition_var

Character scalar - name of the column to test.

values_var

Character scalar - expression that yields the value to assign where the condition matches.

Value

The updated data.table (modified in place).

Details

The values_var argument is parsed and evaluated inside data[, ...], which means it can be a bare column name or a small data.table-style expression. The function modifies data by reference (via data.table::setDT()) and also returns it invisibly to allow chaining.

Examples

dt <- data.frame(line = c("MTPL", "CASCO", "MTPL"), premium = c(100, 200, 300))
create_find_columns(
  data = dt,
  condition_names = c("MTPL", "CASCO"),
  new_cols_names = c("MTPL_premium", "CASCO_premium"),
  condition_var = "line",
  values_var = "premium"
)
#> Index: <line>
#>      line premium MTPL_premium CASCO_premium
#>    <char>   <num>        <num>         <num>
#> 1:   MTPL     100          100             0
#> 2:  CASCO     200            0           200
#> 3:   MTPL     300          300             0