stringByAppendingPathComponent、stringByAppendingString等语句的区别

NSString *a1=@"Hello";

NSString *a2=@"World";

 

NSString *and1=[a1 stringByAppendingString:a2];

NSString *and2=[a1 stringByAppendingPathComponent:a2];//Append附加,path路径,component组成

NSString *and3=[a1 stringByAppendingPathExtension:a2];//extension扩大，延长（扩展名）

NSString *and4=[a1 stringByAppendingFormat:@"_123456_%@",a2];//format格式

  

NSLog(@"%@",and1);

NSLog(@"%@",and2);

NSLog(@"%@",and3);

NSLog(@"%@",and4);

/*******************************/

2015-11-05 20:52:12.500 test[10068:192356] HelloWorld
2015-11-05 20:52:12.501 test[10068:192356] Hello/World
2015-11-05 20:52:12.501 test[10068:192356] Hello.World

2015-11-05 20:52:12.502 test[10068:192356] Hello_123456_World

/*******************************/