How can I add a boolean value to a NSDictionary? - objective-c

Question

Well, for integers I would use NSNumber. But YES and NO aren't objects, I guess. A.f.a.i.k. I can only add objects to an NSDictionary, right?
I couldn't find any wrapper class for booleans. Is there any?

Answer 1

You use NSNumber.
It has init... and number... methods that take booleans, just as it does integers and so on.
From the NSNumber class reference:
// Creates and returns an NSNumber object containing a
// given value, treating it as a BOOL.
+ (NSNumber *)numberWithBool:(BOOL)value
and:
// Returns an NSNumber object initialized to contain a
// given value, treated as a BOOL.
- (id)initWithBool:(BOOL)value
and:
// Returns the receiver’s value as a BOOL.
- (BOOL)boolValue

Answer 2

The new syntax since Apple LLVM Compiler 4.0
dictionary[#"key1"] = #(boolValue);
dictionary[#"key2"] = #YES;
The syntax converts BOOL to NSNumber, which is acceptable to NSDictionary.

Answer 3

If you are declaring it as a literal and you are using clang v3.1 or above, you should use #NO / #YES if you are declaring it as a literal. E.g.
NSMutableDictionary* foo = [#{ #"key": #NO } mutableCopy];
foo[#"bar"] = #YES;
For more info on that:
http://clang.llvm.org/docs/ObjectiveCLiterals.html

Answer 4

As jcampbell1 pointed out, now you can use literal syntax for NSNumbers:
NSDictionary *data = #{
// when you always pass same value
#"someKey" : #YES
// if you want to pass some boolean variable
#"anotherKey" : #(someVariable)
};

Answer 5

Try this:
NSMutableDictionary *dic = [[NSMutableDictionary alloc] init];
[dic setObject:[NSNumber numberWithBool:TRUE] forKey:#"Pratik"];
[dic setObject:[NSNumber numberWithBool:FALSE] forKey:#"Sachin"];
if ([dic[#"Pratik"] boolValue])
{
NSLog(#"Boolean is TRUE for 'Pratik'");
}
else
{
NSLog(#"Boolean is FALSE for 'Pratik'");
}
if ([dic[#"Sachin"] boolValue])
{
NSLog(#"Boolean is TRUE for 'Sachin'");
}
else
{
NSLog(#"Boolean is FALSE for 'Sachin'");
}
The output will be as following:
Boolean is TRUE for 'Pratik'
Boolean is FALSE for 'Sachin'