如何使用NSPredicate CONTAINS IN数组获取所有项目 [英] How to get all items with NSPredicate CONTAINS IN array

问题描述

我有一个对象数组，每个对象都有一个id，我想获取item.objectID包含在id数组中的所有项目，我如何得到该结果？

I have an array of objects and each has an id, and i want to get all items where item.objectID contains in an array of ids, how can i get that result ?

我尝试执行的操作，但是在创建predicateWithFormat时出错：无法解析格式字符串：

What i tried to do but i have an error on creating predicateWithFormat: Unable to parse the format string:

NSString *predicateFormat = [NSString stringWithFormat:@"SELF.itemID CONTAIN IN (1,2,3,4,5,6,7,8)"];
NSPredicate *predicate = [NSPredicate predicateWithFormat: predicateFormat];
filteredData = [localData filteredArrayUsingPredicate:predicate];

我就是要避免这种情况：

I just what to avoid this:

NSString *predicateFormat = [NSString stringWithFormat:@"SELF.itemID = 1 OR SELF.itemID = 2 OR SELF.itemID = 3"];
NSPredicate *predicate = [NSPredicate predicateWithFormat: predicateFormat];
filteredData = [localData filteredArrayUsingPredicate:predicate];

因为还有其他条件要添加以进行过滤。

because there is other condition to add for filter.

推荐答案

您几乎拥有了：）

    NSArray *objects = @[
        @{
            @"itemID" : @1
        },
        @{
            @"itemID" : @2
        },
        @{
            @"itemID" : @3
        },
        @{
            @"itemID" : @4
        },
        @{
            @"itemID" : @5
        }
    ];

    NSArray *idsToLookFor = @[@3, @4];
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"itemID IN %@", idsToLookFor];
    NSArray *result = [objects filteredArrayUsingPredicate:predicate];

    NSLog(@"result: %@", result);

如果您不希望传递任何数组，而是将谓词写在手中，语法为：

And if you do not want to pass in any array, but write the predicate "in hand", the syntax would be:

NSPredicate *predicate = [NSPredicate predicateWithFormat:@"itemID IN { 3, 4 }"];

结果将是：

result: (
        {
        itemID = 3;
    },
        {
        itemID = 4;
    }
)

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