iOS Copy 与 MutableCopy

用不可变容器类创建的对象 进行的copy 是指针复制，没有创建对象，进行的mutableCopy不再是地址拷贝，是全新的对象，容器内的对象还是指针复制

    NSObject *myObj = [[NSObject alloc] init];
    myObj.myTitle = @"my title";
    
    NSObject *myObj2 = [[NSObject alloc] init];
    myObj2.myTitle = @"my title2";

    NSObject *myObj3 = [[NSObject alloc] init];
    myObj3.myTitle = @"my title3";

    NSArray *array = @[myObj,myObj2,myObj3];
    NSArray *arrayRetain = array;
    NSArray *arrayCopy = array.copy;
    NSMutableArray *mArrayCopy = array.mutableCopy;
    
    NSLog(@"----------------------------------------------------------------------------------");
    NSLog(@"%p-------%@",array,array);
    NSLog(@"%p-------%@",arrayRetain,arrayRetain);
    NSLog(@"%p-------%@",arrayCopy,arrayCopy);
    NSLog(@"%p-------%@",mArrayCopy,mArrayCopy);

用可变的容器创建的对象 进行copy，mutableCopy不是指针复制，都是创建了全新的对象，容器内的对象还是指针复制

    NSMutableArray *mArray = [NSMutableArray arrayWithArray:@[myObj,myObj2,myObj3]];
    
    NSArray *arrayRetain = mArray;
    NSArray *arrayCopy = mArray.copy;
    NSMutableArray *mArrayCopy = mArray.mutableCopy;

    NSLog(@"----------------------------------------------------------------------------------");
    NSLog(@"%p-------%@",mArray,mArray);
    NSLog(@"%p-------%@",arrayRetain,arrayRetain);
    NSLog(@"%p-------%@",arrayCopy,arrayCopy);
    NSLog(@"%p-------%@",mArrayCopy,mArrayCopy);
    
    NSLog(@"----------------------------------------------------------------------------------");
    [mArray removeAllObjects];
    NSLog(@"%p-------%@",mArray,mArray);
    NSLog(@"%p-------%@",arrayRetain,arrayRetain);
    NSLog(@"%p-------%@",arrayCopy,arrayCopy);
    NSLog(@"%p-------%@",mArrayCopy,mArrayCopy);

    NSArray *array = [NSMutableArray arrayWithArray:@[myObj,myObj2,myObj3]];

不可变的非容器类对象 copy 只是地址复制。mutableCopy不是地址复制，创建了新的对象

    NSString *string = @"string";
    NSString *stringCopy = string.copy;
    NSMutableString *mStringCopy = string.mutableCopy;
    
    NSLog(@"%p-------%@",string,string);
    NSLog(@"%p-------%@",stringCopy,stringCopy);
    NSLog(@"%p-------%@",mStringCopy,mStringCopy);

可变的非容器类对象copy 、mutableCopy不是地址复制，创建了新的对象

    NSString *mString = [NSMutableString stringWithString:@"string"];
    NSString *stringCopy = mString.copy;
    NSMutableString *mStringCopy = mString.mutableCopy;
    
    NSLog(@"%p-------%@",mString,mString);
    NSLog(@"%p-------%@",stringCopy,stringCopy);
    NSLog(@"%p-------%@",mStringCopy,mStringCopy);