ios上的一些数据转换

NSArray，NSStrng，NSDictionary,NSData  JSON的互转

NSArray *arr = [NSArray arrayWithObject:@"1"];

数组或字典转JSON

 NSString *str = [arr JSONString];  

JSON转数组或字典

 

NSArray *arr1 = [str objectFromJSONString];

 JSON串转化为NSData

 NSData *data = [arr1 JSONData];                

 NSdata转为为NSString

NSString *str1 = [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding];

 NSString转化为NSData

 NSData *data1 = [str1 dataUsingEncoding:NSUTF8StringEncoding]; 

NSData转NSString

 

NSString *str=[logArray componentsJoinedByString:@","];