如何在数组中查找布尔值？

Question

I have an array of objects, each containing a bool value with yes or no. I want to copy all objects with bool YES to another array. How can i do that? i have considered filtering the array using a predicate or integrating it in a for-loop, but i cant seem to get it right.

I need something like this:

for (BOOL* opslag_Set in [dataSource allKeys]){
    NSArray *array = [dataSource objectForKey:opslag_Set];
    for (int j = 0; j < [array count]; j++) {
        if ([[array objectAtIndex:j] isEqualToString:@"YES"]) {
            add object to another array;
        }
    }
}

First object of my array:

    },
    {
    Dato = "2012-11-07 16:20:57 +0000";
    Forfatter = "Vej 51, st. tv.";
    Indhold = "Referat af beboerm\U00f8de";
    "Opslag_set" = 0;
    Overskrift = "Beboerm\U00f8de";
    Prioritet = 0;
    Svar =         (
                    {
            Dato = "2012-11-07 16:23:07 +0000";
            Forfatter = "6. tv.";
            Indhold = "Fedt fedt fedt";
        }
    );
},

Answer 1

You will have to use NSNumber in order to store the bools in an array.

Assuming your boolean array is called boolArray , the code to get an array with only YES would be something like this:

NSMutableArray* temp = [NSMutableArray new];
for (NSNumber* value in boolArray)
{
    if ([value boolValue])
    {
        [temp addObject:[NSNumber numberWithBool:YES]];
    }
}

However, why are you trying to do this? This will return an array with a certain number of elements that are all the same. You could just count the number if that's what you want. The other thing I can think of is that you have an object with a bool property, in which case you can easily adapt the code above.

EDIT: OK, let's assume that we have an object called MyDataObject that has a bool property - NSNumber* boolProperty . Here is the code:

NSMutableArray* temp = [NSMutableArray new];
for (MyDataObject* value in boolArray)
{
    if ([value.boolProperty boolValue])
    {
        [temp addObject:value];
    }
}

This should work for what you are doing. temp will reference the original objects - they are not being copied.