厚积薄发，滴水穿石

Sorting

• – sortedArrayHint
• – sortedArrayUsingFunction:context:
• – sortedArrayUsingFunction:context:hint:
• – sortedArrayUsingDescriptors:
• – sortedArrayUsingSelector:
• – sortedArrayUsingComparator:
• – sortedArrayWithOptions:usingComparator:

- (NSArray *)sortedArrayUsingSelector:(SEL)comparator

Parameters

comparator

A selector that identifies the method to use to compare two elements at a time. The method should returnNSOrderedAscending if the receiving array is smaller than the argument, NSOrderedDescending if the receiving array is larger than the argument, and NSOrderedSame if they are equal.

//selector定义了一个比较两个数组元素的方法，如果此方法返回NSOrderedAscending说明此元素比参数元素小，如果返回NSOrderedDescending说明接收的数组元素比参数元素大，NSOrderedSame相等。

Example:

一个元素为NSString的数组可以通过调用NSString类中的caseInsensitiveCompare:方法作为Selector。

假设anArray已经存在：

 NSArray *sortedArray =

         [anArray sortedArrayUsingSelector:@selector(caseInsensitiveCompare:)];