问题描述
如何使用 Scala Stream 读取大型 CSV 文件(> 1 Gb)?你有代码示例吗?或者您会使用不同的方式读取大型 CSV 文件而不先将其加载到内存中?
How do I read a large CSV file (> 1 Gb) with a Scala Stream? Do you have a code example? Or would you use a different way to read a large CSV file without loading it into memory first?
推荐答案
只需使用您已经说过的 Source.fromFile(...).getLines.
Just use Source.fromFile(...).getLines as you already stated.
这将返回一个已经是惰性的迭代器(您可以将流用作惰性集合，您希望之前检索的值被记忆化，以便您可以再次读取它们)
That returns an Iterator, which is already lazy (You'd use stream as a lazy collection where you wanted previously retrieved values to be memoized, so you can read them again)
如果您遇到内存问题，那么问题将出在您在 getLines 之后正在做什么.任何像 toList 这样强制严格收集的操作都会导致问题.
If you're getting memory problems, then the problem will lie in what you're doing after getLines. Any operation like toList, which forces a strict collection, will cause the problem.
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