CODEWITHSUNDEEP
objective-cnspredicate
GP89
GP89

Reputation: 6730

NSPredicate to match string with an array of prefixes

I'm unsure how to write this NSPredicate to achieve the following. I have an array of prefixes, and I want to know if any of them (plus an underscore) are the prefix of a given string. I don't need to know which matched, just a yes/no if any matched at all.

I can't seem to work this out, at the moment I have this

#import <Foundation/Foundation.h>

int main(int argc, char *argv[]) {
    @autoreleasepool {
        NSArray *bins = @[@"aaa", @"bbb", @"ccc"];
        NSString* item = @"aaa_blah";

        NSPredicate *pred = [NSPredicate predicateWithFormat:@"%@ BEGINSWITH SELF", item];

        NSLog(@"%@", [[bins filteredArrayUsingPredicate:pred] count] ? @"YES" : @"NO");
    }
}

The only way I could think of doing it was filtering the array - so firstly is there a better approach?

And secondly, I want it to return true only if the prefix is followed by an underscore so

@[@"aaa", @"bbb", @"ccc"];

@"aaa_blah"; // YES
@"aaablah"; // NO
@"bbbblah"; // NO

I'm not sure how to do that?

Upvotes: 1

Views: 1224

Answers (1)

meth
meth

Reputation: 1885

+(void)checkIfExists:(NSArray *)prefixes inMyobjects:(NSArray *)myObjects withDivider:(NSString *)divider
{
    divider = @"_";
    prefixes = @[@"aaa",@"bbb",@"ccc"];
    myObjects = @[@"aaa_sd",@"dsf_ds",@"aaa_sss",@"aaabbb"];

    NSMutableArray * resultsOfPredicate = [NSMutableArray new];

    for (NSString * pre in prefixes)
    {
        NSString * iAmLookingFor = [NSString stringWithFormat:@"%@%@", pre, divider];

        NSPredicate *prefixPredicate = [NSPredicate predicateWithFormat:@"SELF beginsWith[c] %@", iAmLookingFor];

        NSArray * resultOfSearch = [myObjects copy];

        resultOfSearch = [resultOfSearch filteredArrayUsingPredicate:prefixPredicate];

        NSLog(@"ros %@",resultOfSearch);

        [resultsOfPredicate addObject:@([resultOfSearch count])];
    }

    for (int i = 0; i<[resultsOfPredicate count]; i++)
    {
        NSLog(@"prefix %@ isAppeared:%d",[prefixes objectAtIndex:i], [[resultsOfPredicate objectAtIndex:i] boolValue]);
    }
}

I hope this will help.

Upvotes: 3

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