使用NSPredicate基于多个键进行过滤（NOT值为key） [英] Using NSPredicate to filter based on multiple keys (NOT values for key)

问题描述

我有以下NSArray包含NSDictionary：

I have the following NSArray containing NSDictionary(s):

NSArray *data = [[NSArray alloc] initWithObjects:
                 [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInt:1], @"bill", [NSNumber numberWithInt:2], @"joe", nil],
                 [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInt:3], @"bill", [NSNumber numberWithInt:4], @"joe", [NSNumber numberWithInt:5], @"jenny", nil],
                 [NSDictionary dictionaryWithObjectsAndKeys:[NSNumber numberWithInt:6], @"joe", [NSNumber numberWithInt:1], @"jenny", nil],
                 nil];

我想创建一个过滤的NSArray只包含NSDictionary匹配多个'keys' NSPredicate。

I am wanting to create a filtered NSArray that only contains objects where the NSDictionary matches multiple 'keys' using NSPredicate.

例如：

• 过滤数组以仅包含NSDictionary对象具有键bill和joe[所需结果：新NSArray将包含两个NSDictionary对象]


• 过滤数组以仅包含NSDictionary对象具有键joe和jenny[希望的结果：new NSArray将包含两个NSDictionary对象]

任何人都可以解释NSPredicate的格式来实现这一点？

Can anyone please explain the format of the NSPredicate to achieve this?

编辑：
我可以使用以下方法实现类似的结果： / p>

I can achieve a similar outcome to desired NSPredicate using:

NSMutableArray *filteredSet = [[NSMutableArray alloc] initWithCapacity:[data count]];
NSString *keySearch1 = [NSString stringWithString:@"bill"];
NSString *keySearch2 = [NSString stringWithString:@"joe"];

for (NSDictionary *currentDict in data){
    // objectForKey will return nil if a key doesn't exists.
    if ([currentDict objectForKey:keySearch1] && [currentDict objectForKey:keySearch2]){
        [filteredSet addObject:currentDict];
    }
}

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

我想象NSPredicate会更加优雅，如果存在？

I'm imagining NSPredicate would be more elegant if one exists?

推荐答案

他们只有我知道是结合两个条件像'value1'IN列表AND'value2'IN列表

they only way I know is to combine two conditions like "'value1' IN list AND 'value2' IN list"

self。@ allKeys应该返回字典的所有键（self是数组中的每个字典）。如果你不用前缀@写它，那么字典只会寻找一个allKeys而不是 - （NSArray *）allKeys的方法。

self.@allKeys should return all the keys of the dictionary (self is each dictionary in your array). If you don't write it with the prefix @ then the dictionary will just look for a key that is "allKeys" instead of the method "- (NSArray*) allKeys"

代码：

NSArray* billAndJoe = [data filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"%@ IN self.@allKeys AND %@ IN self.@allKeys" , @"bill",@"joe" ]];


NSArray* joeAndJenny = [data filteredArrayUsingPredicate:[NSPredicate predicateWithFormat:@"%@ IN self.@allKeys AND %@ IN self.@allKeys" , @"joe",@"jenny" ]]

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