Parse numbers

fast_parse_double() parses decimal and scientific notation, Inf, -Inf, Infinity and NaN in any case, with a leading - or +, after trimming ASCII whitespace. The result is correctly rounded: the nearest double to the decimal value, ties to even, on every platform.

Usage

fast_parse_double(x)

fast_parse_integer(x)

Arguments

x

A character vector.

Value

A double vector (fast_parse_double()) or an integer vector (fast_parse_integer()) of the same length as x.

Details

This is not exactly as.numeric(): R accumulates digits in long double and is not correctly rounded, so the two differ in the last bit for roughly one ordinary decimal in five thousand ("0.799012" is one), and R's result depends on whether it was built with long double. Hexadecimal input, which as.numeric() accepts, is not accepted.

fast_parse_integer() parses a decimal integer and returns NA for anything that is not one or does not fit an R integer, rather than going through a double as as.integer() does: "1.5", "1e3" and "3000000000" are all NA.

Invalid input is NA with no warning.

Examples

fast_parse_double(c("1.5", " -2e-3 ", "+inf", "0x10", "abc", NA))
#> [1]  1.500 -0.002    Inf     NA     NA     NA
fast_parse_integer(c("42", "+7", "2147483647", "2147483648", "1.0"))
#> [1]         42          7 2147483647         NA         NA