Note: information on this page refers to Ceylon 1.1, not to the current release.

Float literals

A literal notation for a Float value.


A Float literal can be written in a variety of ways:

variable Float one = 1.0;
one = 1.0000;

variable Float oneMillion = 1000000.0;
oneMillion = 1_000_000.0;
oneMillion = 1.0M;
oneMillion = 1.0e6;
oneMillion = 1.0E+6;

variable Float half = 0.5;
half = 5.0E-1;
half = 5.0e-1;
half = 500m;
half = 500.0m;


Decimal point

Float literals almost always contain a decimal point, ., which:

  • separates the fractional part from the whole number part, and
  • syntactically distinguishes a Float literal from an Integer literal.

The exception to this rule is any Float literal with a one of the "fractional" magnitude suffices (m, u, n, p, f).

Decimal magnitude suffices

A Float literal may be written with a magnitude, a whole magnitude:

  • k (kilo), 103
  • M (mega), 106
  • G (giga), 109
  • T (tera), 1012
  • P (peta), 1015

Or a fractional magnitude:

  • m (milli), 10-3
  • u (micro), 10-6 (strictly this should be mu (μ), but that would be too hard to type on most keyboards)
  • n (nano), 10-9
  • p (pico), 10-12
  • f (femto), 10-15

For example:

Float million = 1.0M;
Float millionth = 1u;

Grouping digits

An underscore, _, may be used to separate groups of three digits in the integer or fractional part of the literal.

Float million = 1_000_000.0;
Float millionth = 0.000_000_1;

Exponential notation

Exponential notation is supported using e or E to separate the mantissa (before the E) from the scale (after the E).

Float million = 2.0e6;
Float millionth = 2.0e-6;

As a primary

Invoking members of the class Float directly on a literal is permitted:

Float minusOneHalf = 0.5.negativeValue;

See also