

Joel explains mapreduce - npguy
http://www.joelonsoftware.com/items/2006/08/01.html

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ericHosick
I think this post does a really good job of explaining map and reduce.

However, I don't quite agree with this: "Without understanding functional
programming, you can't invent MapReduce".

It is possible to do map/reduce using an object paradigm without functors (or
even functions/methods).

Example:

    
    
        object reduce = new Reduce {
          array = new CompositeThing { ... },
          action = new ActionThing { ... }
        };
        
        float r = reduce.runAsFloat;
    

where CompositeThing can be an actual composite or a reference to a composite
(a key/ value store for example) and ActionThing is a composition of objects
that define the operation on a single entity in the CompositeThing.

