[英]Handling exceptions in Scala collections
You have a Scala collection (an iterator, in this case) that you wish to filter
or map
, where the function doing so can raise an exception. 您有一个Scala集合(在本例中是一个迭代器),您希望filter
或map
,这样做的函数可以引发异常。 You don't want the entire resulting collection being thrown out - only that member. 您不希望抛出整个结果集合 - 只有该成员。 How do you do that? 你是怎样做的?
I tried doing something like: 我尝试过这样的事情:
collection.filter(Try(_.predicate))
but wasn't able to get that to work (and am not sure that that's the proper idiom in the first place!) 但是无法让它发挥作用(并且我不确定这首先是正确的成语!)
You're very close. 你很近。 Try something like: 尝试类似的东西:
collection.filter(x => Try(x.predicate).getOrElse(false))
Depends on which you want to do. 取决于你想做什么。 In the case of filter
, the predicate still needs to be boolean, and Try[T]
is most certainly not. 在filter
的情况下,谓词仍然需要是布尔值,而Try[T]
肯定不是。 Try
does have handy getOrElse
and toOption
methods which could help us convert cases of Failure
to None
. Try
有方便的getOrElse
和toOption
方法,可以帮助我们将Failure
案例转换为None
。
collection.filter(x => Try(predicate).getOrElse(false))
For map
if you wish to throw out the failures, you can do something like this: 对于map
如果你想抛弃失败,你可以这样做:
collection.flatMap(x => Try(...).toOption)
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