How to sum properties of the objects within an array in Ruby

Posted by Ernst Fitschen on Stack Overflow See other posts from Stack Overflow or by Ernst Fitschen
Published on 2012-06-30T09:12:24Z Indexed on 2012/06/30 9:15 UTC
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ruby

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arrays

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object

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sum

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inject

I understand that in order to sum array elements in Ruby one can use the inject method, i.e.

array = [1,2,3,4,5]; puts array.inject(0, &:+)

But how do I sum the properties of objects within an object array e.g.

There's an array of objects and each object has a property "cash" for example. So I want to sum their cash balances into one total. Something like...

array.cash.inject(0, &:+) (but this doesn't work)

I realise I could probably make a new array composed only of the property cash and sum this, but I'm looking for a cleaner method if possible!

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