简单的理解深拷贝和浅拷贝

1.深拷贝浅拷贝定义 :

A.浅拷贝只拷贝值，不开辟新的内存空间
B.深拷贝，不但拷贝值还开辟新的内存空间

2.Foundation框架下默认支持copy的对象类型有：

NString、NSArray、NSNumber、NSDictionar、NSMutableString、NSMutablerArray、NSMutableDictionary等

3.我这里只对 NSString/ NSMutableString/ NSArray /NSMutableArray 测试 （只做借鉴使用）

 //1.string
        //1.1 NSString测试
        NSString *str = @"hanmengmeng";
        
        NSString *copyStr = [str copy]; //浅拷贝
        NSMutableString * copymuStr = [[NSMutableString alloc] init];
        copymuStr = [str copy];//copy时 可变字符串等同于不可变字符 浅拷贝
        
        NSLog(@"str %p,copyStr %p, copymuStr %p",str,copyStr,copymuStr);
        
        
        NSString *mutableCopyStr = [str mutableCopy];//深拷贝
        NSMutableString * mutableCopyMuStr = [[NSMutableString alloc] init];
        mutableCopyMuStr = [str mutableCopy]; //深拷贝
        
        NSLog(@"str %p, mutableCopyStr %p, mutableCopyStr %p",str,mutableCopyStr,mutableCopyMuStr);

image.png

        //1.2 NSMutableString测试 （可变）
        NSMutableString *mustr = [NSMutableString stringWithFormat:@"hahah"];

        NSString *copystr  = [mustr copy];//深拷贝
        NSMutableString * copymustr = [[NSMutableString alloc] init];
        copymustr = [mustr copy];//深拷贝

        NSLog(@"mustr %p ,copystr %p, copymustr %p",mustr,copystr, copymustr);

        NSString *mutableCopystr = [mustr mutableCopy]; //深拷贝
        NSMutableString * mutableCopymuStr = [[NSMutableString alloc] init];
        mutableCopymuStr = [mustr mutableCopy];//深拷贝

        NSLog(@"mustr %p ,mutableCopystr %p, mutableCopymuStr %p",mustr,mutableCopystr, mutableCopymuStr);

image.png

        //2.array
        //2.1 NSArray 测试
        NSArray *array = [NSArray arrayWithObjects:@"han",@"meng",@"meng", nil];

        NSArray *copyArray = [array copy]; //浅拷贝
        NSMutableArray *copymuArray = [[NSMutableArray alloc] init];
        copymuArray = [array copy]; //浅拷贝

        NSLog(@"array %p ,copyArray %p, copymuArray %p",array,copyArray, copymuArray);

        NSArray *mutableCopyArray = [array mutableCopy];  //深拷贝
        NSMutableArray *mutableCopymuArray = [[NSMutableArray alloc] init];
        mutableCopymuArray = [array mutableCopy];  //深拷贝

        NSLog(@"array %p ,mutableCopyArray %p, mutableCopymuArray %p",array,mutableCopyArray, mutableCopymuArray);

image.png

 //2.2 NSMutableArray 测试
        NSMutableArray * marray =[[NSMutableArray alloc] initWithObjects:@"a",@"b",@"c" ,nil];

        NSArray *copyMArray = [marray copy]; //深拷贝
        NSMutableArray *copymMarray = [[NSMutableArray alloc] init];
        copymMarray = [marray copy]; //深拷贝

        NSLog(@"array %p ,copyMArray %p, copymMarray %p",array,copyMArray, copymMarray);

        NSArray *mutableCopyMArray = [marray mutableCopy]; //深拷贝
        NSMutableArray *mutableCopymMarray = [[NSMutableArray alloc] init];
        mutableCopymMarray = [marray mutableCopy]; //深拷贝

        NSLog(@"array %p ,mutableCopyMArray %p, mutableCopymMarray %p",array,mutableCopyMArray, mutableCopymMarray);

image.png

4. 不可变类型的copy是浅拷贝 可变的类型copy和mutableCopy都是深拷贝 （个人观点，仅供参考）

5.附加 脑袋抽抽测试

 // 3.对象 通过实现NSCopying协议如下的唯一方法来达到对象拷贝的效果 所以不能用copy 或者 mutableCopy
        NSObject * obj = [[UIView alloc] init];
        NSObject * copyObj = [obj copy];
        NSObject * mutableCopyobj = [obj mutableCopy];
        NSLog(@"%p,%p,%p",obj,copyObj,mutableCopyobj);
//要用这两个方法,这是代理方法，别忘了遵守协议
- (id)copyWithZone:(nullable NSZone *)zone;
- (id)mutableCopyWithZone:(nullable NSZone *)zone;