数据类型转换

import “RootViewController.h”

@interface RootViewController ()

@end

@implementation RootViewController

• (void)viewDidLoad {
  [super viewDidLoad];
  // Do any additional setup after loading the view.
  //********************NSString 相关***********************//
  //NSDictionary 转NSString
  //用字符串将nsarray的元素拼接起来
  NSArray *array = [NSArray arrayWithObjects:@”hello”,@”world”, nil];
  NSString *string = [array componentsJoinedByString:@” “];
  NSLog(@”string = %@”,string );

  //nsdata 转 nsstring
  NSString *strurl = @”www.”;
  NSURL *url = [NSURL URLWithString:strurl];
  NSData *data = [NSData dataWithContentsOfURL:url];
  NSString *datastr1 = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];

  // NSString 转换成NSData 对象

  NSData* Data = [@”testdata” dataUsingEncoding:NSUTF8StringEncoding];

  // NSData 转换成char*

  NSData *data2;
  const char* a=[data2 bytes];

  //nsstring zhuan char
  NSString *str = @”dad”;
  const char *q =[str UTF8String];

  // char* 转换成NSData对象

  Byte* tempData = malloc(sizeof(Byte)*16);
  NSData *content=[NSData dataWithBytes:tempData length:16];

// NSNumber转NSString:

// 假设现有一NSNumber的变量A，要转换成NSString类型的B

// 方法如下：

NSNumberFormatter* numberFormatter = [[NSNumberFormatter alloc] init];NSNumber *A = [[NSNumber alloc]initWithInt:5];NSString *B;B = [numberFormatter stringFromNumber:A];[numberFormatter release];

// nsstring和float 还有int之间的转换

NSString *tempA = @"123";NSString *tempB = @"456";

// 1，字符串拼接

NSString *newString = [NSString stringWithFormat:@"%@%@",tempA,tempB];

// 2，字符转int

int intString = [newString intValue];

// 3，int转字符

NSString *stringInt = [NSString stringWithFormat:@"%d",intString];

//4，字符转float

float floatString = [newString floatValue];

// 5，万能公式其他转字符

NSString *stringFloat = [NSString stringWithFormat:@"%f",floatString];

//

}
//nsdictionary 相关
//字典nsdictionary 转成json
- (NSString )dictionaryToJason:(NSDictionary )dic
{
NSData *jsondata = [NSJSONSerialization dataWithJSONObject:dic options:NSJSONWritingPrettyPrinted error:nil];
return [[NSString alloc]initWithData:jsondata encoding:NSUTF8StringEncoding];

}

• (void)didReceiveMemoryWarning {
  [super didReceiveMemoryWarning];
  // Dispose of any resources that can be recreated.
  }

/*

pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
// Get the new view controller using [segue destinationViewController].
// Pass the selected object to the new view controller.
}
*/

@end