iOS 内存管理~集合对象的copy和mutableCopy

//联系人:石虎QQ: 1224614774昵称:嗡嘛呢叭咪哄

一、集合&不可变

集合类对象是指NSArray、NSDictionary、NSSet ... 之类的对象。

NSArray* arr =@[@[@"a",@"b"], [@[@"c",@"d"]mutableCopy],@"AA", [NSMutableStringstringWithString:@"a"]];

NSArray*arrCy = [arrcopy];

NSMutableArray*arrMCy = [arrmutableCopy];

//!分别打印变量的内存地址及对象地址

NSLog(@"   arr :%p  %p  [%p %p %p %p]", arr, &arr, arr[0], arr[1], arr[2], arr[3]);

NSLog(@" arrCy :%p  %p  [%p %p %p %p]", arrCy, &arrCy, arrCy[0], arrCy[1], arrCy[2], arrCy[3]);

NSLog(@"arrMCy :%p  %p  [%p %p %p %p]", arrMCy, &arrMCy, arrMCy[0], arrMCy[1], arrMCy[2], arrMCy[3]);

//!输出

arr :0x1004034300x7fff5fbff7a0[0x1004012600x1004032a00x1000010d80x1004033a0]

arrCy :0x1004034300x7fff5fbff798[0x1004012600x1004032a00x1000010d80x1004033a0]

arrMCy :0x1004034f00x7fff5fbff790[0x1004012600x1004032a00x1000010d80x1004033a0]

从打印结果结论:

浅拷贝 :操作是不可变集合的copy

单层深拷贝:操作是拷贝不可变集合的mutableCopy

集合内部的元素仍然是浅拷贝,无论该元素是否是集合是否可变

二、集合&可变

NSMutableArray* arr = [NSMutableArray arrayWithObjects:@[@"a",@"b"], [NSMutableArray arrayWithObject:@"A"],@"AA", [NSMutableString stringWithString:@"a"],nil];

NSArray* arrCy = [arr copy];

NSMutableArray* arrMCy = [arr mutableCopy];

NSLog(@"   arr :%p  %p  [%p %p %p %p]", arr, &arr, arr[0], arr[1], arr[2], arr[3]);

NSLog(@" arrCy :%p  %p  [%p %p %p %p]", arrCy, &arrCy, arrCy[0], arrCy[1], arrCy[2], arrCy[3]);

NSLog(@"arrMCy :%p  %p  [%p %p %p %p]", arrMCy, &arrMCy, arrMCy[0], arrMCy[1], arrMCy[2], arrMCy[3]);

arr :0x1005023d00x7fff5fbff7d0[0x1005000d00x1005021400x1000010b80x100502320]

arrCy :0x1005025000x7fff5fbff7c8[0x1005000d00x1005021400x1000010b80x100502320]

arrMCy :0x1005025c00x7fff5fbff7c0[0x1005000d00x1005021400x1000010b80x100502320]

可以看出

可变集合的copy和mutableCopy都是单层深拷贝

集合拷贝结论

集合copymutableCopy

不可变对象浅单层深

可变对象单层深单层深

谢谢!!!