as.Numeric: Coerce to numeric

In tdeenes/eegR: Analyze EEG Signals

Description

as.Numeric is similar to as.numeric except that 1) it results in an error for character strings for which as.numeric would send a warning, 2) keeps integer, Date and POSIXt objects as they are (i.e. does not convert them to double), 3) coerces logicals to integer, not double, 4) keeps 'dim' and 'dimnames' attributes if requested, and 5) always copies the original object, even if no actual coercion occurs. as.Numeric_ returns the original object if possible and does not alter the shape of multidimensional inputs.

Usage

as.Numeric(x, keep_dim = FALSE)

as.Numeric_(x)

Arguments

x	the object to coerce
keep_dim	logical value whether dim and dimnames attributes should be preserved. The default is FALSE. (But note that as.Numeric_ does not have this argument, because it always preserves both attributes.)

Value

as.Numeric returns the original object (at the same memory address) if it is numeric (that is, is.numeric(x) returns TRUE) or inherits "Date" or "POSIXt" classes. Otherwise, it returns a double vector if as.numeric is successful and stops with an error if as.numeric results in a warning or error.

Functions

• as.Numeric_: Modify by reference

Examples

# if 'x' is double, as.Numeric() simply returns it, just like as.numeric()
x <- rnorm(10)
stopifnot(identical(as.numeric(x), as.Numeric(x)))

# if 'x' is integer, as.Numeric() simply returns it,
# but as.numeric() converts to double
x <- 1:10
stopifnot(identical(x, as.Numeric(x)))
stopifnot(all.equal(as.numeric(x), as.Numeric(x))) # not fully identical!

# if 'x' is Date or POSIXt, as.Numeric() simply returns it
x1 <- as.Date("2013-03-14")
x2 <- as.POSIXlt(x1)
stopifnot(identical(x1, as.Numeric(x1)))
stopifnot(identical(x2, as.Numeric(x2)))

# if 'x' contains only numeric-like characters (or NAs),
# as.Numeric() returns the same as as.numeric()
x <- c(NA, as.character(1:10))
stopifnot(identical(as.numeric(x), as.Numeric(x)))

# if 'x' contains any non-numeric characters (e.g. letters),
# as.Numeric() returns an error
x <- c("a", as.character(1:10))
x_num <- try(as.Numeric(x), silent = TRUE)
stopifnot(inherits(x_num, "try-error"))

# if 'x' is a matrix or array, as.Numeric() converts it to a vector by
# default, just like as.numeric()
( y <- x <- matrix(rnorm(10), 5, 2) )
( x_num <- as.Numeric(x) )
stopifnot(is.null(attr(x_num, "dim")))

# however, you can ask to keep the original shape
( x_num2 <- as.Numeric(x, TRUE) )

# if you use as.Numeric_() instead, it keeps the shape
( x_num3 <- as.Numeric_(x) )
stopifnot(identical(x_num3, x))

# note that since 'x' is numeric, no coercion is needed, so
# so as.Numeric_() does not create a copy, but as.Numeric() does
address(x)
address(x_num2)
address(x_num3)
stopifnot(identical(address(x), address(x_num3)))

tdeenes/eegR documentation built on April 19, 2021, 4:17 p.m.