# Programming Ruby ### The Pragmatic Programmer's Guide
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class Method |
Parent: | Object
Version: | 1.6

### Index:

[ ] arity call to_proc

Method objects are created by `Object#method` , and are associated with a particular object (not just with a class). They may be used to invoke the method within the object, and as a block associated with an iterator.

`class Thing`
`def square(n)`
`n*n`
`end`
`end`
`aThing = Thing.new`
`aMethod = aThing.method("square")`
``
`aMethod.call(9)` | » | `81`
`[ 1, 2, 3 ].collect(&aMethod)` | » | `[1, 4, 9]`

instance methods
[ ] | meth[ [ args ]* ] -> anObject
|  | Synonym for `Method.call`.
arity | meth.arity -> aFixnum
|  | Returns an indication of the number of arguments accepted by a method. Returns a nonnegative integer for methods that take a fixed number of arguments. For Ruby methods that take a variable number of arguments, returns -n-1, where n is the number of required arguments. For methods written in C, returns -1 if the call takes a variable number of arguments.
call | meth.call( [ args ]* ) -> anObject
|  | Invokes the meth with the specified arguments, returning the method's return value.
`m = 12.method("+")`
`m.call(3)` | » | `15`
`m.call(20)` | » | `32`
to_proc | meth.to_proc -> aProc
|  | Returns a `Proc` object corresponding to this method.

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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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