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Determining type of an object in ruby
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The proper way to determine the "type" of an object, which is a wobbly term in the Ruby world, is to call object.class.
Since classes can inherit from other classes, if you want to determine if an object is "of a particular type" you might call object.is_a?(ClassName) to see if obje...
What is the difference between indexOf() and search()?
Being fairly new to JavaScript, I'm unable to discern when to use each of these.
8 Answers
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Listing only directories in UNIX
I want to list only the directories in specified path ( ls doesn't have such option).
Also, can this be done with a single line command?
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Is there a version control system for database structure changes?
...rules to downgrade the version (such as removing a column). Each migration is numbered, and a table keeps track of your current db version.
To migrate up, you run a command called "db:migrate" which looks at your version and applies the needed scripts. You can migrate down in a similar way.
The mi...
Django. Override save for model
... or just description updated, so I can skip rescaling every time the model is saved?
7 Answers
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ElasticSearch, Sphinx, Lucene, Solr, Xapian. Which fits for which usage? [closed]
... why I went ahead and created it in the first place :).
Using pure Lucene is challenging. There are many things that you need to take care for if you want it to really perform well, and also, its a library, so no distributed support, it's just an embedded Java library that you need to maintain.
In...
Mediator Vs Observer Object-Oriented Design Patterns
...he observer pattern:
Class A, can have zero or more observers of type O registered with it. When something in A is changed it notifies all of the observers.
The mediator pattern:
You have some number of instances of class X (or maybe even several different types:X, Y & Z), and they wish to comm...
Java Enum Methods - return opposite direction enum
...tion, that has a method that returns the opposite direction (the following is not syntactically correct, i.e, enums cannot be instantiated, but it illustrates my point). Is this possible in Java?
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How to get maximum value from the Collection (for example ArrayList)?
There is an ArrayList which stores integer values. I need to find the maximum value in this list. E.g. suppose the arrayList stored values are : 10, 20, 30, 40, 50 and the max
value would be 50 .
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What is the ultimate postal code and zip regex?
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There is none.
Postal/zip codes around the world don't follow a common pattern. In some countries they are made up by numbers, in others they can be combinations of numbers an letters, some can contain spaces, others dots, the num...