ios - 如何评估 NSPredicate 中的 NSDictionary

Question

我有一个有两个数组的字典，字典是

NSDictionary * StudentDetails = [NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:StudentIDs,StudentNames, nil] forKeys:[NSArray arrayWithObjects:@"ID",@"NAME", nil]];

两个数组是

NSArray * StudentIDs = [NSArray arrayWithObjects:@"07bg1234",@"07ac1234", nil];
NSArray * StudentNames = [NSArray arrayWithObjects:@"aaaaaaa",@"bbbbb", nil];

我尝试使用谓词来检索数组值作为

NSString * searchStr = @"07bg1234";

    NSPredicate * fileExtPredicate01 = [NSPredicate predicateWithFormat:@"SELF IN %@", StudentIDs];

    if (([fileExtPredicate01 evaluateWithObject: searchStr]== YES)) {
        NSLog(@"Student ID: %@ Exists",searchStr);
    }
    else {
        NSLog(@"Student ID: %@ not Exists",searchStr);
    }

到目前为止它工作正常....当我试图将字典值作为

NSPredicate * fileExtPredicate02 = [NSPredicate predicateWithFormat:@"SELF IN %@", StudentDetails];

    if (([fileExtPredicate02 evaluateWithObject: searchStr]== YES)) {
        NSLog(@"Student Details: %@ Exists",searchStr);
    }
    else {
        NSLog(@"Student Details: %@ not Exists",searchStr);
    }

我总是得到 o/p 作为 Student Details **** not Exists... 我怎样才能使用谓词在字典中得到 'searchStr' 是否存在？？？？提前致谢

Answer 1

使用 @"SELF IN %@.ID"。

我构建了以下通过的单元测试。

NSArray * StudentIDs = [NSArray arrayWithObjects:@"07bg1234",@"07ac1234", nil];
NSArray * StudentNames = [NSArray arrayWithObjects:@"aaaaaaa",@"bbbbb", nil];
NSDictionary * StudentDetails = [NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:StudentIDs,StudentNames, nil] forKeys:[NSArray arrayWithObjects:@"ID",@"NAME", nil]];
NSString *searchStr = @"07bg1234";

NSPredicate * fileExtPredicate02 = [NSPredicate predicateWithFormat:@"SELF IN %@.ID", StudentDetails];

XCTAssert([fileExtPredicate02 evaluateWithObject:searchStr]);

---

更新

为了获得 ID 和 NAME，我使用了。

NSArray * StudentIDs = [NSArray arrayWithObjects:@"07bg1234",@"07ac1234", nil];
NSArray * StudentNames = [NSArray arrayWithObjects:@"aaaaaaa",@"bbbbb", nil];
NSDictionary * StudentDetails = [NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:StudentIDs,StudentNames, nil] forKeys:[NSArray arrayWithObjects:@"ID",@"NAME", nil]];

NSPredicate * fileExtPredicate02 = [NSPredicate predicateWithFormat:@"SELF IN %@.ID OR SELF IN %@.NAME", StudentDetails, StudentDetails];

XCTAssert([fileExtPredicate02 evaluateWithObject:@"07bg1234"]);
XCTAssert([fileExtPredicate02 evaluateWithObject:@"aaaaaaa"]);

我觉得这很麻烦，我认为使用 SUBQUERY() 会有更好的答案，但我必须再考虑一下。

---

更新 2

因此，如果您能忍受一些奇怪的事情，这里是 SUBQUERY() 版本。谓词是 SUBQUERY(%@, $value, SELF IN $value).@count > 0。 SUBQUERY(%@, $value, SELF IN $value) 返回匹配值数组，如果至少有 1 个匹配项，则 .@count > 0 返回 true。与前面的示例不同，我没有传递 StudentDetails。我需要传递 StudentDetails.allValues。

NSArray * StudentIDs = [NSArray arrayWithObjects:@"07bg1234",@"07ac1234", nil];
NSArray * StudentNames = [NSArray arrayWithObjects:@"aaaaaaa",@"bbbbb", nil];
NSDictionary * StudentDetails = [NSDictionary dictionaryWithObjects:[NSArray arrayWithObjects:StudentIDs,StudentNames, nil] forKeys:[NSArray arrayWithObjects:@"ID",@"NAME", nil]];

NSPredicate * fileExtPredicate02 = [NSPredicate predicateWithFormat:@"SUBQUERY(%@, $value, SELF IN $value).@count > 0", StudentDetails.allValues];

XCTAssert([fileExtPredicate02 evaluateWithObject:@"07bg1234"]);
XCTAssert([fileExtPredicate02 evaluateWithObject:@"aaaaaaa"]);