Using NSPredicate to filter array of arrays

Question

I have the following situation:

NSArray(
    NSArray(
        string1,
        string2,
        string3,
        string4,
        string5,
    )
    ,
    NSArray(
        string6,
        string7,
        string8,
        string9,
        string10,
   )
)

Now I need a predicate that returns the array that contains a specific string. e.g. Filter Array that contains string9 -> I should get back the entire second array because I need to process the other strings inside that array. Any ideas?

Solution 1

Just for completeness: It can be done using predicateWithFormat::

NSArray *array = @[
    @[@"A", @"B", @"C"],
    @[@"D", @"E", @"F"],
];

NSString *searchTerm = @"E";
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"ANY SELF == %@", searchTerm];
NSArray *filtered = [array filteredArrayUsingPredicate:predicate];
NSLog(@"%@", filtered);

Output:

(
    (
        D,
        E,
        F
    )
)

Solution 2

From what I know you can't do it as a one-liner so instead of using predicateWithFormat: you should use predicateWithBlock:

Something like this should do what you want

NSString *someString = @"Find me"; // The string you need to find.
NSArray *arrayWithArrayOfStrings = @[]; // Your array
[arrayWithArrayOfStrings filteredArrayUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(NSArray *evaluatedArray, NSDictionary *bindings) {
    return [evaluatedArray indexOfObject:someString] != NSNotFound;
 }]];

Update: Martin R proved me wrong :)

Comments

[Anupdas]

+1, I was working on this with SUBQUERY, [NSPredicate predicateWithFormat:@"SUBQUERY(SELF, $content, $content == [c] %@)",string] but this didn't work. Any pointers?

[Martin R]

@Anupdas: You were almost there, @"SUBQUERY(SELF, $content, $content == [c] %@).@count > 0" works.

[Anupdas]

@MartinR Awesome, it works. So the result of the subquery should be equated to some for even forming the predicate. Thanks :)

[Martin R]

@Anupdas: Exactly, the SUBQUERY returns a set, but the predicate must evaluate to true or false.

[Meghs Dhameliya]

is it possible to get only E as element of nested array