Programming Ruby: The Pragmatic Programmer's Guide

# 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 © 2000 Addison Wesley Longman, Inc. Released under the terms of the Open Publication License V1.0.
This reference is available for download.