NumericConstants {base} | R Documentation

## Numeric Constants

### Description

How R parses numeric constants.

### Details

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.

### See Also

`Syntax`.

`Quotes` for the parsing of character constants,

[Package base version 2.2.1 Index]