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    <p>A predicate like</p> <pre><code>[NSPredicate predicateWithFormat:@"self isMemberOfClass: %@", [MyClass class]] </code></pre> <p>actually works. It returns <em>exactly the same predicate</em> as the (documented)</p> <pre><code>[NSComparisonPredicate predicateWithLeftExpression:[NSExpression expressionForEvaluatedObject] rightExpression:[NSExpression expressionForConstantValue:[MyClass class]] customSelector:@selector(isMemberOfClass:)] </code></pre> <p>The problem in your case could be that <code>isMemberOfClass:</code> compares for class <em>equality</em>, so this would not match objects which are members of a subclass of <code>MyClass</code>.</p> <p>This could happen if <code>MyClass</code> is a class cluster and <code>myObject</code> is an instance of a concrete subclass. For example:</p> <pre><code>NSString *myString = [[NSString alloc] initWithUTF8String:"hello world"]; Class c1 = [NSString class]; // NSString Class c2 = [myString class]; // __NSCFString BOOL b1 = [myString isMemberOfClass:c1]; // NO BOOL b2 = [myString isMemberOfClass:c2]; // YES </code></pre> <p>In that case <code>[myObject class]</code> and <code>[MyClass class]</code> are different, which would explain why one predicate works and the other predicate does not work.</p> <p>The following code uses <code>isKindOfClass:</code> instead and produces the expected result:</p> <pre><code>NSArray *array = @[@"123", @456, [NSArray array]]; NSPredicate* predicate = [NSPredicate predicateWithFormat:@"self isKindOfClass: %@", [NSNumber class]]; NSArray* predicateResults = [array filteredArrayUsingPredicate:predicate]; NSLog(@"%@", predicateResults); // Output: ( 456 ) </code></pre>
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    1. PONSPredicate isKindOfClass only works for [myObject class] not for [MyClass class]
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    1. USMartin R
    1. USMartin R
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    1. PONSPredicate isKindOfClass only works for [myObject class] not for [MyClass class]
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    1. COJust found the `predicateWithLeftExpression:rightExpression:customSelector:` in the docs when I saw your edit :). Still, this is not well documented for the `predicateWithFormat:` method.
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      1. USGuillaume Algis
    2. CO@GuillaumeAlgis: Yes, unfortunately the "Predicate Programming Guide" is not covering all aspects. Another important topic which is almost undocumented is "SUBQUERY".
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      1. USMartin R
    3. CO"In that case [myObject class] and [MyClass class] are different" Why would `[myObject class]` and `[MyClass class]` be different?
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      1. USnewacct
 

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