ios中常用数据类型相互转换

ios中常用数据类型相互转换

//1. NSMutableArray和NSArray互转

// NSArray转为NSMutableArray

NSMutableArray *arrM = [arr mutableCopy]; //方法1

NSMutableArray *arrM = [NSMutableArray arrayWithArray:arr]; //方法2

// NSMutableArray转为NSArray

NSArray *arr = [arrM copy]; //方法1

NSArray *arr = [NSArray arrayWithArray: arrM]; //方法2

//2. NSData和NSString互转

// NSData转为NSString

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

// NSString转为NSData对象

NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding];

//3. NSString和NSURL互转

// NSString转为NSURL

NSString *str = @"http://www.baidu.com/天气/20160315"; //含有中文字符的str需要先编码，才能转为url

NSString *urlStr = [str stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];

NSURL *url = [NSURL URLWithString:urlStr];

// NSURL转为NSString

NSString *urlStr = [url absoluteString];

NSString *str = [urlStr stringByReplacingPercentEscapesUsingEncoding:NSUTF8StringEncoding]; //将编码的字转换成汉字

//4. 字典和模型互转

// KVC将字典转为模型

[model setValuesForKeysWithDictionary:dict];

// KVC将模型转为数组

NSDictionary *dict = [model dictionaryWithValuesForKeys:@[@"name",@"age",@"dog"] ];

//5. NSArray和NSData互转

// NSArray转为NSData

NSData *data = [NSKeyedArchiver archivedDataWithRootObject: array];

// NSData转为NSArray

NSArray *array = [NSKeyedUnarchiver unarchiveObjectWithData: data];