2013-07-12 OC常用数据类型

来源：互联网发布：简单的化工制图软件编辑：程序博客网时间：2024/06/03 17:00

面试考点

//不可变字符串也能添加新的字符，只不过它已经产生了一个新的字符串对象，跟原来的那个已经没有关系了

//可变字符串 NSMutableString

//可变和不可变的区别
//可变的操作的是始终是同一块内存，不可变操作的不是同一块内存，他会产生不同内存

可变字符串是不可变字符串的子类，同时它扩充了自己的新的方法

字符串：

self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];

// Override point for customization after application launch.

self.window.backgroundColor = [UIColor whiteColor];

//字符串

NSString *str1 = [[NSString alloc]initWithString:@"ios"];

NSLog(@"str1 = %@",str1);

// [str1 release];

int a = 10;

NSString *str2 = [[NSString alloc]initWithFormat:@"%d",a];

NSLog(@"str2 len = %d",str2.length);//字符串长度

NSLog(@"str2 = %@",str2);

// [str2 release];

//字符串拼接

// NSString *str3 = [str1 stringByAppendingString:str2];

NSString *str3 = [str1 stringByAppendingFormat:@"%d",7];

NSLog(@"str3 = %@",str3);

NSString *str4 = @"123456789";

NSString *str5 = [str4 substringFromIndex:0];

NSLog(@"str5 = %@",str5);

NSString *str6 = [str4 substringToIndex:4];

NSLog(@"str6 = %@",str6);

NSRange r1 = {2,3};

NSString *str7 = [str4 substringWithRange:r1];

NSLog(@"str7 = %@",str7);

//查找字符串

NSRange r2 = [str4 rangeOfString:@"145"];

if (r2.location == NSNotFound)

{

NSLog(@"Not Found!");

}

//+stringWithContentOfFile:encoding:error;

// -initWithContentsOfFile:encoding:error;

//utf-8编码

//字符串的转换函数

NSString *str8 = @"123.45";

double d = [str8 doubleValue];

NSLog(@"%lf",d);

//比较字符串

NSString *str9 = @"123";

NSString *str10 =@"456";

if ([str9 isEqualToString:str10])

{

NSLog(@"相等");

}

NSComparisonResult r = [str9 compare:str10];//NSComparisonResult 是枚举类型的

NSLog(@"r = %d",r);//输出-1 表示升序

//判断对象是否相等

if ([str9 isEqual:str10])

{

NSLog(@"相等");

}

else

{

NSLog(@"不相等");

}

//大小写转换应用验证码 lowercaseString uppercaseString

//可变字符串 NSMutableString

//可变和不可变的区别

//可变的操作的是同一块内存，不可变操作的不是同一块内存，他会产生不同内存

NSMutableString *str11 = [[NSMutableString alloc]initWithCapacity:10];

[str11 appendString:@"ios"];//appendingString appendingFormat, 追加字符串

[str11 appendFormat:@"%d",7];

NSRange r3 = {3,1};

[str11 deleteCharactersInRange:r3];

NSLog(@"str11 = %@",str11);

//不可变字符串也能添加新的字符，只不过它已经产生了一个新的字符串对象，跟原来的那个已经没有关系了

[self.window makeKeyAndVisible];

return YES;

集合

数组指针 char *str = {"ios","andriod","html"};

OC集合（容器）分类

1）数组Array
2）字典Dictionary
3）集合set
在集合（容器）中添加一个对象，这个对象的引用计数会增加一，且控制权归系统。你只能释放当初你alloc的那个引用计数，添加对象时增加的那个引用计数会在容器被销毁时有系统自动释放。

数组NSArray

是不可变列表集合
1）可以存在多个对象（对象可以为同一类型，也可为不同的类型）
2）每个对象使用下标来表示
3）最后以nil结束

self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];

// Override point for customization after application launch.

self.window.backgroundColor = [UIColor whiteColor];

//数组NSArray

NSArray *arry = [[NSArray alloc]initWithObjects:@"ios",@"wphone",@"Android", nil];//初始化

// NSArray *arry = [NSArray alloc]initWithObjects:@"ios",@"wphone",@"android", nil];

//获取数组里面元素的个数

//获取数组中元素

NSString *str = [arry objectAtIndex:0];

NSLog(@"str = %@",str);

//数组长度

NSLog(@"arrcount = %d",arry.count);

[arry release];

//遍历数组对象方法一

arry = [NSArray arrayWithObjects:@"ios",@"html5",@"cocoa2D", nil];

for (int i = 0; i < arry.count; i++) {

NSString *str = [arry objectAtIndex:i];

NSLog(@"str1 = %@",str);

}

//遍历数组对象方法二

for (NSString *str in arry){

NSLog(@"str = %@",str);

}

//可变数组NSMutableArray

NSMutableArray *array2 = [[NSMutableArray alloc]initWithCapacity:10];

//添加元素

[array2 addObject:@"C#"];

[array2 addObjectsFromArray:arry];

for (NSString *str in array2)

{

NSLog(@"arry2 = %@",array2);

}

NSLog(@"arry2 = %@",array2);

//在数组中小括号里面的都是数组

//在集合（容器）中添加一个对象，这个对象的引用计数会增加一，且控制权归系统。

NSString *str3 = [[NSString alloc]initWithFormat:@"%d",10];

NSLog(@"str3 retainCount:%d",str3.retainCount);

[array2 addObject:str3];

NSLog(@"str3 retainCount:%d",str3.retainCount);

//移除元素

[array2 removeLastObject:@"C#"];

[array2 removeObjectAtIndex:0];

[array2 removeObjectsInArray:array2];

NSRange r4 = {1,3};

[array2 removeObjectsInRange:r4];

NSLog(@"arry = %@",array2);

//替换元素

[array2 replaceObjectAtIndex:1 withObject:@"xml"];

NSLog(@"arry2 = %@",array2);

[str3 release];

[array2 release];

[self.window makeKeyAndVisible];

return YES;

字典Dictionary
键值存储
key一般是字符串
字典存储的对象无序的，使用key来表示每个对象

字典

1）创建字典
2）获取对象
3）获取所有的key
4）获取所有对象
5）字典在控制台是用｛｝包起来的，但是在字典中时以键值对的形式存放的

控制台的输出：

2013-07-12 17:04:57.447 OC_7[2050:c07] mDic = {

key3 = valu3;

key4 = valu4;

key5 = valu5;

key6 = valu6;

}

self.window = [[[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]] autorelease];

// Override point for customization after application launch.

self.window.backgroundColor = [UIColor whiteColor];

//字典Dictionary

NSArray *arry = [NSArray arrayWithObjects:@"html",@"ios", nil];

//创建字典初始化

NSDictionary *dic =[[NSDictionary alloc]initWithObjectsAndKeys:@"valu1",@"key1",arry,@"key2", nil];

NSLog(@"dic count = %d",dic.count);

//取元素

NSString *str = [dic valueForKey:@"key1"];

NSLog(@"str = %@",str);

NSString * arry1 = [dic valueForKey:@"key2"];

NSLog(@"arry1 = %@",arry1);

NSArray *arry2 = [dic allKeys];//key是一个数组

NSArray *arry3 = [dic allValues];

//遍历所有的key，返回一个数组,因为key是数组所以是可以遍历的

for (NSString *key in [dic allKeys]) {

NSLog(@"%@",[dic allKeys]);

}

//可变字典

NSMutableDictionary *mDic = [NSMutableDictionary dictionaryWithCapacity:10];

[mDic setObject:@"valu3" forKey:@"key3"];

[mDic setObject:@"valu4" forKey:@"key4"];

[mDic setObject:@"valu5" forKey:@"key5"];

[mDic setObject:@"valu6" forKey:@"key6"];

//打印字典内容

NSLog(@"mDic = %@",mDic);

[mDic removeObjectForKey:@"key6"];

NSLog(@"mDic = %@",mDic);

NSLog(@"mDic = %u",mDic.count);

for (NSString *key2 in [mDic allKeys]){

NSLog(@"%@",[mDic allKeys]);

}

//获取所有的key

[dic release];

[self.window makeKeyAndVisible];

return YES;

集合set
集合时无序的，其存储的对象不允许出现重复的
创建，添加，删除，求交集，补集，差集