# Programming Ruby

### The Pragmatic Programmer's Guide

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class Float
 Parent: Numeric Version: 1.6

### Index:

Arithmetic operations <=> ceil finite? floor infinite? nan? round to_f to_i to_s

`Float` objects represent real numbers using the native architecture's double-precision floating point representation.

instance methods
Arithmetic operations

Performs various arithmetic operations on flt.

 flt + aNumeric Addition flt -- aNumeric Subtraction flt * aNumeric Multiplication flt / aNumeric Division flt % aNumeric Modulo flt ** aNumeric Exponentiation

<=> flt <=> aNumeric -> -1, 0, +1

Returns -1, 0, or +1 depending on whether flt is less than, equal to, or greater than aNumeric. This is the basis for the tests in `Comparable`.

ceil flt.ceil -> anInteger

Returns the smallest `Integer` greater than or equal to flt.

 `1.2.ceil` » `2` `2.0.ceil` » `2` `(-1.2).ceil` » `-1` `(-2.0).ceil` » `-2`

finite? flt.finite? -> `true` or `false`

Returns `true` if flt is a valid IEEE floating point number (it is not infinite, and `nan?` is `false`).

floor flt.floor -> anInteger

Returns the largest integer less than or equal to flt.

 `1.2.floor` » `1` `2.0.floor` » `2` `(-1.2).floor` » `-2` `(-2.0).floor` » `-2`

infinite? flt.infinite? -> `nil`, -1, +1

Returns `nil`, -1, or +1 depending on whether flt is finite, -infinity, or +infinity.

 `(0.0).infinite?` » `nil` `(-1.0/0.0).infinite?` » `-1` `(+1.0/0.0).infinite?` » `1`

nan? flt.nan? -> `true` or `false`

Returns `true` if flt is an invalid IEEE floating point number.

 `a = -1.0` » `-1.0` `a.nan?` » `false` `a = Math.log(a)` » `NaN` `a.nan?` » `true`

round flt.round -> anInteger

Rounds flt to the nearest integer. Equivalent to:

 ```def round   return floor(self+0.5) if self > 0.0   return ceil(self-0.5)  if self < 0.0   return 0.0 end ```

 `1.5.round` » `2` `(-1.5).round` » `-2`

to_f flt.to_f -> flt

Returns flt.

to_i flt.to_i -> anInteger

Returns flt truncated to an `Integer`.

to_s flt.to_s -> aString

Returns a string containing a representation of self. As well as a fixed or exponential form of the number, the call may return ```NaN`'', ```Infinity`'', and ```-Infinity`''.

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Extracted from the book "Programming Ruby - The Pragmatic Programmer's Guide"
Copyright © 2001 by Addison Wesley Longman, Inc. This material may be distributed only subject to the terms and conditions set forth in the Open Publication License, v1.0 or later (the latest version is presently available at http://www.opencontent.org/openpub/)).

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