淺復制：只復制指向對象的指針，而不復制引用對象本身。計數器+1 ,就像比如retain
深層復制：復制引用對象本身。計數器不變，產生新對象
retain：始終是淺復制。引用計數每次加一。返回對象是否可變與被復制的對象保持一致。
copy：對于可變對象為深復制，引用計數不改變;對于不可變對象是淺復制，引用計數每次加一。始終返回一個不可變對象。
mutableCopy：始終是深復制，引用計數不改變。始終返回一個可變對象。
#import <Foundation/Foundation.h>int main(int argc, const char * argv[]) { NSMutableArray *array1=[NSMutableArray arrayWithObjects:@"two day", nil]; NSMutableArray *array2=[array1 copy]; NSArray *array3=[array2 copy]; NSArray *array4=[array2 retain]; NSMutableArray *array5=[array1 retain]; NSMutableArray *array6=[array1 mutableCopy]; NSArray *array7=[array2 mutableCopy]; NSLog(@"-------------"); NSLog(@"array1:%@ %p",array1, array1); NSLog(@"array2:%@ %p",array2, array2); NSLog(@"array3:%@ %p",array3, array3); NSLog(@"array4:%@ %p",array4, array4); NSLog(@"array5:%@ %p",array5, array5); NSLog(@"array6:%@ %p",array6, array6); NSLog(@"array7:%@ %p",array7, array7); NSLog(@"-------------"); return 0;}
2015-04-01 20:46:23.131 04-01-person[2204:165655] -------------2015-04-01 20:46:23.132 04-01-person[2204:165655] array1:( "two day") 0x1001145702015-04-01 20:46:23.133 04-01-person[2204:165655] array2:( "two day") 0x1001147002015-04-01 20:46:23.133 04-01-person[2204:165655] array3:( "two day") 0x1001147002015-04-01 20:46:23.133 04-01-person[2204:165655] array4:( "two day") 0x1001147002015-04-01 20:46:23.133 04-01-person[2204:165655] array5:( "two day") 0x1001145702015-04-01 20:46:23.133 04-01-person[2204:165655] array6:( "two day") 0x1001150d02015-04-01 20:46:23.134 04-01-person[2204:165655] array7:( "two day") 0x100115b002015-04-01 20:46:23.134 04-01-person[2204:165655] -------------PRogram ended with exit code: 0
數組類型轉換：
1、不可變對象→可變對象的轉換：
#import <Foundation/Foundation.h>int main(int argc, const char * argv[]) { NSArray *array01=[NSArray arrayWithObjects:@"zhang",@"wang",@"li", nil]; NSMutableArray *array02=[array01 mutableCopy]; //mutableCopy始終返回一個可變對象 NSLog(@"array01: %@ %p",array01,array01); NSLog(@"array02: %@ %p",array02,array02); return 0;}
2015-04-01 21:00:28.218 04-01-person[2252:170414] array01: ( zhang, wang, li) 0x100106c802015-04-01 21:00:28.220 04-01-person[2252:170414] array02: ( zhang, wang, li) 0x1001076d0Program ended with exit code: 0
2、可變對象→不可變對象的轉換：
#import <Foundation/Foundation.h>int main(int argc, const char * argv[]) { NSMutableArray *array1 = [NSMutableArray arrayWithObjects:@"zhang",@"wang",@"li", nil]; NSArray *array2=[array1 copy];//copy對于可變對象為深復制，引用計數不改變;對于不可變對象是淺復制，引用計數每次加一。始終返回一個不可變對象 NSLog(@"array1: %@ %p",array1,array1); NSLog(@"array2: %@ %p",array2,array2); return 0;}
2015-04-01 21:03:45.349 04-01-person[2263:171615] array1: ( zhang, wang, li) 0x1001129002015-04-01 21:03:45.350 04-01-person[2263:171615] array2: ( zhang, wang, li) 0x1001133b0
3、可變對象→可變對象的轉換（不同指針變量指向不同的內存地址）：
#import <Foundation/Foundation.h>int main(int argc, const char * argv[]) { NSMutableArray *array1= [NSMutableArray arrayWithObjects:@"zhang",@"wang",@"li", nil]; NSMutableArray *array2=[array1 mutableCopy]; NSLog(@"array1: %@ %p",array1,array1); NSLog(@"array2: %@ %p",array2,array2); return 0;}
2015-04-01 20:57:41.732 04-01-person[2243:169571] array1: ( zhang, wang, li) 0x1001145702015-04-01 20:57:41.734 04-01-person[2243:169571] array2: ( zhang, wang, li) 0x100115020Program ended with exit code: 0
4、同類型對象之間的指針復制（不同指針變量指向同一塊內存地址）：
#import <Foundation/Foundation.h>int main(int argc, const char * argv[]) { NSArray *array1=[NSArray arrayWithObjects:@"one",@"two",@"three", nil]; NSArray *array2=[array1 copy]; NSLog(@"array1: %@ %p",array1,array1); NSLog(@"array2: %@ %p",array2,array2); return 0;}
2015-04-01 20:53:07.398 04-01-person[2217:167996] array1: ( one, two, three) 0x1006069a02015-04-01 20:53:07.399 04-01-person[2217:167996] array2: ( one, two, three) 0x1006069a0Program ended with exit code: 0
當多個指針同時指向同一塊內存區域，那么這些個指針同時擁有對該內存區的所有權。所有權的瓜分過程，這時候就要用到淺拷貝了。
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