Difference between revisions of "Ruby on Rails"
From Hawk Wiki
| Line 6: | Line 6: | ||
<h3>nil?, empty? and blank?</h3> | <h3>nil?, empty? and blank?</h3> | ||
| − | < | + | <pre> |
.nil? can be used on any object and is true if the object is nil. | .nil? can be used on any object and is true if the object is nil. | ||
| Line 14: | Line 14: | ||
Array length == 0 | Array length == 0 | ||
Hash length == 0 | Hash length == 0 | ||
| + | |||
Running .empty? on something that is nil will throw a NoMethodError. | Running .empty? on something that is nil will throw a NoMethodError. | ||
| Line 25: | Line 26: | ||
" ".blank? == true | " ".blank? == true | ||
" ".empty? == false | " ".empty? == false | ||
| − | </ | + | </pre> |
Revision as of 18:10, 16 September 2013
Tutorials
Beginner's tutorial
http://allaboutruby.wordpress.com/2006/01/09/installing-rails-on-windows-step-by-step-tutorial/
Ruby in 20 minutes
http://www.ruby-lang.org/en/documentation/quickstart/
nil?, empty? and blank?
.nil? can be used on any object and is true if the object is nil.
.empty? can be used on strings, arrays and hashes and returns true if:
String length == 0
Array length == 0
Hash length == 0
Running .empty? on something that is nil will throw a NoMethodError.
.blank? will operate on any object
nil.blank? == true
false.blank? == true
[].blank? == true
{}.blank? == true
"".blank? == true
5.blank? == false
" ".blank? == true
" ".empty? == false
