| NumericConstants {base} | R Documentation |
How R parses numeric constants.
R parses numeric constants in its input in a very similar way to C floating-point constants.
Inf and NaN are numeric constants. All
other numeric constants start with a digit or period.
Hexadecimal constants start with 0x or 0X followed by
a non-empty sequence from 0-9 a-f A-F which is interpreted as a
hexadecimal number.
Decimal constants consists of a nonempty sequence of digits possibly
containing a period (the decimal point), optionally followed by a
decimal exponent. A decimal exponent consists of an E or
e followed by an optional plus or minus sign followed by a
non-empty sequence of digits, and indicates multiplication by a power
of ten.
A numeric constant immediately followed by i is regarded as an
imaginary complex number.
Only the ASCII digits 0–9 are recognized as digits, even in languages which have other representations of digits. The ‘decimal separator’ is always a period and never a comma.
Note that a leading plus or minus is not part of numeric constant but a unary operator applied to the constant.
Quotes for the parsing of character constants,