Objective-c Setobject:forkey: And Setvalue:forkey: the difference

Setobject:forkey: Is the method of the Nsmutabledictionary class

The key parameter type can be any type of objectvalue cannot be nil, or it will be an error Setvalue:forkey: Is the method of the NSObject class, which means that all OC objects have this methodThe key value must be a stringvalue can be nil, but when value is null, the Removeobject:forkey method is called automatically

1, note: Setobject:forkey: objects can not be stored nil to be distinguished from the following situation:

[Imagedictionarysetobject:[nsnullnull] forkey:indexnumber];[NSNull null] represents an empty object, not nil, note this 2, Setobject:forkey: When key is NSNumber object, the following:[Imagedictionarysetobject:obj forkey:[nsnumber numberwithint:10];

Objective-c Setobject:forkey: And Setvalue:forkey: the difference