Hi Monks!

Let's say I have an array of object. and also assume that there are some attributes (attr1, attr2, ...attrn) in each object.

I would like to have function/class that can count over any attributes' values. e.g if object is person, and person has attributes, sex ('Male','Female'), ethnic ('a','b','c',...), occupation ('programmer','hacker',...).

If I want to find count# on sex => 
    count( array_of_objects, 'sex') => returns
   ( 'Male' => 45 #male count, 'Female' => 54)

[download]
But in some cases, I would also need to group, 
   count(array, ['sex','occupation']) =>
   (   'Male' => ( 'programmer' => 10, 'blah' => 34),
       'Female' => ('blah' => 3, 'programmer'=>4)

[download]
How could I have generic function/class to group and count over collection?

In reply to SQL like query over iterable in perl by pwagyi

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