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Does guava (or another java library) have something like reduce() function in Python?
I'm looking for something like this http://docs.python.org/library/functions.html#reduce
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The arguments against reduce are that it tends to be misapplied, harms readability and doesn't fit in with the non-functional orientation of Python.
Python's reduce() is a function that implements a mathematical technique called folding or reduction. reduce() is useful when you need to apply a function to an iterable and reduce it to a single cumulative value.
Indeed, the reduce is much faster than the for when using iadd in the for.
Reduce function is an inbuilt function in python whose major task is to give aggregate value as an output. Syntactically it is written as; reduce(func,iter_obj) here reduce operation will be done on “func” function and “iter_obj” is implying the iterable data values used to return result of output.
No. It might eventually, though functional stuff like that isn't a core focus of Guava. See this issue.
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I've not (yet) managed to find any Java collections libraries that support map and reduce. (I exclude map/reduce functionality in parallel / distributed processing frameworks ... because you need a "big" problem for these frameworks to be worthwhile.)
Probably, the reason for this "lack" is that map/reduce coding without closures is just too cumbersome. Too much boilerplate code, too much heavy-weight syntax. Since the main point of using map / reduce primitives on simple collections is to make your code simple and elegant ...
@CurtainDog contributed a link to lambdaj. That does the kind of thing that the OP is after (though there's no method specifically called reduce). But it illustrates what I was saying about boilerplate. Notice that many of the higher order operations involve creating classes that extend one or other of the Closure classes.
(FWIW, I think that the Lambda.aggregate(...) methods are the lambdaj analog of reduce.)
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