Add or update columns — mutate-table.express • table.express

Add or update columns of a data.table::data.table, possibly by reference using :=.

# S3 method for ExprBuilder
mutate(
  .data,
  ...,
  .sequential = FALSE,
  .unquote_names = TRUE,
  .parse = getOption("table.express.parse", FALSE),
  .chain = getOption("table.express.chain", TRUE)
)

# S3 method for EagerExprBuilder
mutate(.data, ..., .parent_env = rlang::caller_env())

# S3 method for data.table
mutate(.data, ...)

Arguments

.data: An instance of ExprBuilder.
...: Mutation clauses.
.sequential: If TRUE, each expression in ... is assigned to a nested body within curly braces to allow them to use variables created by previous expressions. The default is FALSE because enabling this may turn off some data.table optimizations.
.unquote_names: Passed to rlang::enexprs(). Set to FALSE if you want to pass the single := expression.
.parse: Logical. Whether to apply rlang::parse_expr() to obtain the expressions.
.chain: Logical. Should a new frame be automatically chained to the expression if the clause being set already exists?
.parent_env: See end_expr()

Details

To see more examples, check the vignette, or the table.express-package entry.

Examples


data("mtcars")
data.table::as.data.table(mtcars) %>%
    start_expr %>%
    mutate(mpg_squared = mpg ^ 2)
#> .DT_[, `:=`(mpg_squared = mpg^2)]