如何在NSSet或NSArray中搜索具有特定属性的特定值的对象? [英] How to search an NSSet or NSArray for an object which has an specific value for an specific property?

问题描述

如何在NSSet或NSArray中搜索具有特定属性的特定值的对象?

How to search an NSSet or NSArray for an object which has an specific value for an specific property?

示例:我有一个包含20个对象的NSSet，每个对象都有一个type属性.我想获取第一个具有[theObject.type isEqualToString:@"standard"]的对象.

Example: I have an NSSet with 20 objects, and every object has an type property. I want to get the first object which has [theObject.type isEqualToString:@"standard"].

我记得有可能以某种方式使用谓词，对吗?

I remember that it was possible to use predicates somehow for this kind of stuff, right?

推荐答案

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"type == %@", @"standard"];
NSArray *filteredArray = [myArray filteredArrayUsingPredicate:predicate];
id firstFoundObject = nil;
firstFoundObject =  filteredArray.count > 0 ? filteredArray.firstObject : nil;

NB:在NSSet中找到 first 对象的概念没有意义，因为对象在集合中的顺序是不确定的.

NB: The notion of the first found object in an NSSet makes no sense since the order of the objects in a set is undefined.

这篇关于如何在NSSet或NSArray中搜索具有特定属性的特定值的对象?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！