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iosobjective-cenumerationnsexception

is it possible to check condition based on expression,objective c

My arrays arroriginally contains following

[A,B,C,D,E,F,G];

Now I want to remove A and B and C and I could do it like following

 [arr enumerateObjectsUsingBlock:^(NSString *name, NSUInteger idx, BOOL *stop) {
    if ( [name isEqualToString:@"A"] || [name isEqualToString:@"B"] || [name isEqualToString:@"C"]);
         [arr removeObject:name];
}];

Question : is it possible to do it using nsexpression. It sounds like to define an nsexpression contains A and B and C, then we delete elements based on the nxpression.

Any ideas how to achieve this. All comments are welcomed here. Thanks.

Solution

  • Instead of using NSExpression directly, consider filteredArrayUsingPredicate: or, for NSMutableArray, filterUsingPredicate:. This will either return a new array filtered by the predicate, or the same array, mutated according to the predicate.

    Also, it is not a real good idea to mutate your collection while enumerating.