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]