Difference between revisions of "Ruby on Rails"
From Hawk Wiki
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<h3>nil?, empty? and blank?</h3> | <h3>nil?, empty? and blank?</h3> | ||
| − | .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.<br> |
| − | .empty? can be used on strings, arrays and hashes and returns true if: | + | .empty? can be used on strings, arrays and hashes and returns true if:<br> |
| − | String length == 0 | + | String length == 0<br> |
| − | Array length == 0 | + | Array length == 0<br> |
| − | Hash length == 0 | + | Hash length == 0<br> |
| − | Running .empty? on something that is nil will throw a NoMethodError. | + | Running .empty? on something that is nil will throw a NoMethodError.<br> |
| − | .blank? will operate on any object | + | .blank? will operate on any object<br> |
| − | nil.blank? == true | + | nil.blank? == true<br> |
| − | false.blank? == true | + | false.blank? == true<br> |
| − | [].blank? == true | + | [].blank? == true<br> |
| − | {}.blank? == true | + | {}.blank? == true<br> |
| − | "".blank? == true | + | "".blank? == true<br> |
| − | 5.blank? == false | + | 5.blank? == false<br> |
| − | " ".blank? == true | + | " ".blank? == true<br> |
| − | " ".empty? == false | + | " ".empty? == false<br> |
Revision as of 18:09, 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
