Programmering i Ruby

Den Pragmatiske Programmerers Veiledning
Forrige < Innhold ^
Neste >
klassen NilClass
Forelder: Object
Versjon: 1.6

Indeks:

& ^ | nil? to_a to_i to_s

The class of the singleton object nil.

instansmetoder
& nil& anObject -> false

And---Returns false. As anObject is an argument to a method call, it is always evaluated; there is no short-circuit evaluation in this case. 

nil && puts("logical and")
nil &  puts("and")
produces: 
and

^ nil^ anObject -> true or false

Exclusive Or---Returns false if anObject is nil or false, true otherwise.

| nil| anObject -> true or false

Or---Returns false if anObject is nil or false, true otherwise.

nil? nil.nil? -> true

Always returns true.

to_a nil.to_a -> []

Always returns an empty array.

to_i nil.to_i -> 0

Always returns zero.

to_s nil.to_s -> ""

Always returns the empty string.

Forrige < Innhold ^
Neste >

Extracted from the book "Programming Ruby - The Pragmatic Programmer's Guide".
Translation to norwegian by Norway Ruby User Group.
Copyright for the english original authored by David Thomas and Andrew Hunt:
Copyright © 2001 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/).

(Please note that the license for the original has changed from the above. The above is the license of the original version that was used as a foundation for the translation efforts.)

Copyright for the norwegian translation:
Copyright © 2002 Norway Ruby User Group.
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/).
Distribution of substantively modified versions of this document is prohibited without the explicit permission of the copyright holder.
Distribution of the work or derivative of the work in any standard (paper) book form is prohibited unless prior permission is obtained from the copyright holder.