如何得到一个NSArray的第x个元素在Cocoa中?

New to Cocoa, and seem to be missing something.

可可是新手，似乎漏掉了什么。

What is the most elegant/idiomatic way to obtain the first x elements of an NSArray as another NSArray? Obviously I can iterate through them and store them manually, but it seems like there has to be a more standard method of doing this.

获得NSArray的第一个x元素作为另一个NSArray的最优雅/惯用方法是什么?显然，我可以遍历它们并手工存储它们，但似乎必须有更标准的方法来实现这一点。

I was expecting there to be an -arrayWithObjectsInRange: or something similar, but don't see anything...

我原以为会有一个-arrayWithObjectsInRange:或者类似的东西，但什么都没看到……

NSArray* largeArray...// Contains 50 items...

NSArray* smallArray = // fill in the blank     

// smallArray contains first 10 items from largeArray

Thanks!

谢谢!

4 个解决方案

#1

122

You can use subarrayWithRange:.

您可以使用subarrayWithRange:。

NSArray *smallArray = [largeArray subarrayWithRange:NSMakeRange(0, 10)];

#2

firstNItems = [items subarrayWithRange:NSMakeRange(0, MIN(n, items.count))];

#3

2nd parameter is number of array items to include in the range, not the 'to' index

第二个参数是要包含在范围中的数组项的数量，而不是“to”索引

#4

-1

In Swift 3 you can use this:

在Swift 3中，您可以使用以下内容:

let smallArray = largeArray.prefix(10)

#1

122