copy与retain的区别：
1)copy是创建一个新对象，retain是创建一个指针，引用对象计数加1。Copy属性表示两个对象内容相同，新的对象retain为1 ，与旧有对象的引用计数无关，旧有对象没有变化。copy减少对象对上下文的依赖。
2)retain属性表示两个对象地址相同（建立一个指针，指针拷贝），内容当然相同，这个对象的retain值+1也就是说，retain 是指针拷贝，copy 是内容拷贝。
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#pragma mark - iOS系统的集合类与非集合类的retain和copy
// 非容器类（NSString / NSNumber等）
NSString *str1 = [[NSString alloc] initWithFormat:@
"%@"
, @
"Jacedy"
];
NSString *str11 = [str1 retain];
NSString *str12 = [str1 copy];
NSString *str13 = [str1 mutableCopy];
NSMutableString *str2 = [[NSMutableString alloc] initWithString:@
"Jake"
];
NSMutableString *str21 = [str2 retain];
NSMutableString *str22 = [str2 copy];
NSMutableString *str23 = [str2 mutableCopy];
NSLog(@
"非容器类"
);
NSLog(@
"str1 的地址：%p，retainCount：%lu"
, str1, (unsigned
long
)[str1 retainCount]);
NSLog(@
"str11的地址：%p，retainCount：%lu"
, str11, (unsigned
long
)[str11 retainCount]);
NSLog(@
"str12的地址：%p，retainCount：%lu"
, str12, (unsigned
long
)[str12 retainCount]);
NSLog(@
"str13的地址：%p，retainCount：%lu\n\n"
, str13, (unsigned
long
)[str13 retainCount]);
NSLog(@
"str2 的地址：%p，retainCount：%lu"
, str2, (unsigned
long
)[str2 retainCount]);
NSLog(@
"str21的地址：%p，retainCount：%lu"
, str21, (unsigned
long
)[str21 retainCount]);
NSLog(@
"str22的地址：%p，retainCount：%lu"
, str22, (unsigned
long
)[str22 retainCount]);
NSLog(@
"str23的地址：%p，retainCount：%lu\n\n"
, str23, (unsigned
long
)[str23 retainCount]);
// 容器类（集合类）（NSArray / NSSet等）
NSArray *arr1 = [NSArray arrayWithObjects:@
"one"
, @
"two"
, nil];
NSArray *arr11 = [arr1 retain];
NSArray *arr12 = [arr1 copy];
NSArray *arr13 = [arr1 mutableCopy];
NSMutableArray *arr2 = [NSMutableArray arrayWithObjects:@
"one"
, @
"two"
, nil];
NSMutableArray *arr21 = [arr2 retain];
NSMutableArray *arr22 = [arr2 copy];
NSMutableArray *arr23 = [arr2 mutableCopy];
NSLog(@
"容器类"
);
NSLog(@
"arr1 的地址：%p，retainCount：%lu"
, arr1, (unsigned
long
)[arr1 retainCount]);
NSLog(@
"arr11的地址：%p，retainCount：%lu"
, arr11, (unsigned
long
)[arr11 retainCount]);
NSLog(@
"arr12的地址：%p，retainCount：%lu"
, arr12, (unsigned
long
)[arr12 retainCount]);
NSLog(@
"arr13的地址：%p，retainCount：%lu"
, arr13, (unsigned
long
)[arr13 retainCount]);
NSLog(@
"arr1[0] :%p"
, arr1[0]);
NSLog(@
"arr13[0]:%p\n\n"
, arr13[0]);
NSLog(@
"arr2 的地址：%p，retainCount：%lu"
, arr2, (unsigned
long
)[arr2 retainCount]);
NSLog(@
"arr21的地址：%p，retainCount：%lu"
, arr21, (unsigned
long
)[arr21 retainCount]);
NSLog(@
"arr22的地址：%p，retainCount：%lu"
, arr22, (unsigned
long
)[arr22 retainCount]);
NSLog(@
"arr23的地址：%p，retainCount：%lu"
, arr23, (unsigned
long
)[arr23 retainCount]);
NSLog(@
"arr2[0] :%p"
, arr2[0]);
NSLog(@
"arr22[0]:%p\n\n"
, arr22[0]);
#pragma mark - NSString 内存管理
NSString *string1 = @
"Jacedy"
;
NSString *string2 = [[NSString alloc] initWithString:@
"KJacedy"
];
NSString *string3 = [[NSString alloc] initWithFormat:@
"Jacedy"
];
NSString *string4 = [NSString stringWithFormat:@
"K-Jacedy"
];
//NSString *string5 = [NSString stringWithString:@"Jacedy"]; //该方法等同于string1
NSLog(@
"NSString内存管理"
);
NSLog(@
"string1:%p retainCount:%lu class:%@"
, string1, [string1 retainCount], [string1
class
]);
NSLog(@
"string2:%p retainCount:%lu class:%@"
, string2, [string2 retainCount], [string2
class
]);
NSLog(@
"string3:%p retainCount:%lu class:%@"
, string3, [string3 retainCount], [string3
class
]);
NSLog(@
"string4:%p retainCount:%lu class:%@\n\n"
, string4, [string4 retainCount], [string4
class
]);
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// 输出结果：
非容器类
str1 的地址：0x79646563614a65，retainCount：18446744073709551615
str11的地址：0x79646563614a65，retainCount：18446744073709551615
str12的地址：0x79646563614a65，retainCount：18446744073709551615
str13的地址：0x100203a70，retainCount：1
str2 的地址：0x100203f20，retainCount：2
str21的地址：0x100203f20，retainCount：2
str22的地址：0x656b614a45，retainCount：18446744073709551615
str23的地址：0x100204040，retainCount：1
容器类
arr1 的地址：0x100300a90，retainCount：3
arr11的地址：0x100300a90，retainCount：3
arr12的地址：0x100300a90，retainCount：3
arr13的地址：0x100301190，retainCount：1
arr1[0] :0x1000021b0
arr13[0]:0x1000021b0
arr2 的地址：0x100301260，retainCount：2
arr21的地址：0x100301260，retainCount：2
arr22的地址：0x100301370，retainCount：1
arr23的地址：0x100301390，retainCount：1
arr2[0] :0x1000021b0
arr22[0]:0x1000021b0
NSString内存管理
string1:0x100002050 retainCount:18446744073709551615
class
:__NSCFConstantString
string2:0x100002390 retainCount:18446744073709551615
class
:__NSCFConstantString
string3:0x79646563614a65 retainCount:18446744073709551615
class
:NSTaggedPointerString
string4:0xd2eec83802a585 retainCount:18446744073709551615
class
:NSTaggedPointerString
Program ended with
exit
code: 0
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深拷贝与浅拷贝结论：
1)对非集合类：
[immutableObject copy] // 浅复制
[immutableObject mutableCopy] //深复制
[mutableObject copy] //深复制
[mutableObject mutableCopy] //深复制
2)对集合类：
[immutableObject copy] // 浅复制
[immutableObject mutableCopy] //单层深复制（即仅对对象本身进行深复制，对象元素仍是浅复制（指针拷贝，内存地址不变））
[mutableObject copy] //单层深复制
[mutableObject mutableCopy] //单层深复制
NSString内存分配结论：
@“” 和 initWithString：方法生成的字符串分配在常量区，系统自动管理内存；
initWithFormat：和 stringWithFormat: 方法生成的字符串分配在堆区，autorelease
