Question

I’m using NSLog(@"%@", [filter attributes]); to print out the following from a dictionary:

CIAttributeFilterDisplayName = "Color Controls";
CIAttributeFilterName = CIColorControls;
inputBrightness =     {
    CIAttributeClass = NSNumber;
    CIAttributeDefault = 0;
    CIAttributeIdentity = 0;
    CIAttributeSliderMax = 1;
    CIAttributeSliderMin = "-1";
    CIAttributeType = CIAttributeTypeScalar;
};

I’m a little confused about NSDictionarys and how the information is organized. If I needed to access the attributes for inputBrightness, what would be the syntax to retrieve this form the dictionary?

Answer 1

If you want to retrieve inputBrightness from dictionary filter, you can try this:

NSDictionary *inputBrightnessDict = filter[@"inputBrightness"]; //or [filter valueForKey:@"inputBrightness"];

This will return another dictionary with key value pairs CIAttributeClass:NSNumber, CIAttributeDefault:0 etc..

You can confirm that filter[@"inputBrightness"] is a dictionary by looking at the NSLog statement. Key value pairs enclosed in { and } represents a dictionary where as ( and ) represents an array.

Inorder to retrieve any value from inputBrightnessDict you can fetch it as, inputBrightnessDict[@"CIAttributeType"];