Using scala to accumulate elementwise sums [duplicate]

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Possible Duplicate:

In Scala, how do I fold a List and return the intermediate results?

I am searching for a functional way of accumulating the elements of a Sorte开发者_如何学CdTree in the following way:

I want a list with containing the sums of all precursors (including the element itself) for all elements in the SortedTree.

For Exmaple:

SortedTree contains (0.4, 0.3, 0.2, 0.1, 0.05)

I want the list: (0,4. 0.7, 0. 9, 1, 1.05)

Any suggestions?

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There is no SortedTree in the standard library, but you just want scanLeft (assuming your type extends TraversableLike):

seq.scanLeft(0.0)(_ + _).tail

or if you want a list:

seq.toList.scanLeft(0.0)(_ + _).tail