scala - Option.zip returns List, not Option -



scala - Option.zip returns List, not Option -

standard library documentation describes zip partial signature def zip[b](that: geniterable[b]): option[(a, b)] some(1) zip some(2) returns list((1,2)) not some((1,2)). case of buggy implementation or buggy documentation?

buggy documentation.

zip defined on iterable, , it's applicable option due implicit conversion option2iterable (this explicitly stated in documentation if closely).

for reason option first converted iterable , zip operation supported.

this done code reuse, misses case in iterable methods create sense straight on option without need of implicit conversion.

here's relevant give-and-take in mailing list: https://groups.google.com/forum/#!topic/scala-language/mfu5ppt_jyw

if need zip 2 options, can utilize workaround:

(opt1 zip opt2).headoption

also, travis noted in comments, alternatively leverage scalaz zip type class, although have utilize fzip instead.

opt1 fzip opt2

scala

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