IEnumerable T与IReadOnlyList< T> [英] IEnumerable<T> vs IReadOnlyList<T>

问题描述

选择IEnumerable<T>与IReadOnlyList<T>作为返回参数类型或输入参数类型有什么区别?

What is the difference between choosing IEnumerable<T> vs IReadOnlyList<T> as a return parameter type or input parameter type?

IEnumerable<T>提供.Count和.ElementAt，这是IReadOnlyList<T>

推荐答案

IEnumerable<T>表示某些数据上的仅前向游标.您可以从收藏的开头到结尾，一次查看一个项目.

IEnumerable<T> represents a forward-only cursor over some data. You can go from start to end of the collection, looking at one item at a time.

IReadOnlyList<T>表示可读的随机访问集合.

IReadOnlyList<T> represents a readable random access collection.

IEnumerable<T>更通用，因为它可以表示动态生成的项目，通过网络传入的数据，来自数据库的行等.另一方面，IReadOnlyList<T>基本上仅表示内存中的集合.

IEnumerable<T> is more general, in that it can represent items generated on the fly, data coming in over a network, rows from a database, etc. IReadOnlyList<T> on the other hand basically represents only in-memory collections.

如果您只需要按顺序查看一次，那么IEnumerable<T>是更好的选择-它更通用.

If you only need to look at each item once, in order, then IEnumerable<T> is the superior choice - it's more general.

我建议实际上看看C ++标准模板库-他们对各种类型的迭代器的讨论实际上可以很好地映射到您的问题.

I'd recommend actually looking at the C++ Standard Template Library - their discussion of the various types of iterators actually maps pretty well to your question.

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