//将NSData转化为NSString
        NSString* str = [[NSString alloc] initWithData:response encoding:NSUTF8StringEncoding];
//将NSString 转化为NSData 
(NSString.h)
- (NSData *)dataUsingEncoding:(NSStringEncoding)encoding;  


//用空格分割

NSString *str1 = @"周一 周三 周五 周六 周二 周日 周四";
NSArray *arr = [str1 componentsSeparatedByString:@" "];

 //载一个字符串中删除一个字符或字符串
[_display deleteCharactersInRange:NSMakeRange(index_of_char_to_remove, 1)];

数学转换为字符串
NSString *returnStr;
returnStr = [[NSNumber numberWithInt:row] stringValue];




     NSString  
     *******************************************************************************************/  
    //一、NSString      
    /*----------------创建字符串的方法----------------*/  
      
    //1、创建常量字符串。  
    NSString *astring = @"This is a String!";  
      
      
    //2、创建空字符串，给予赋值。  
      
    NSString *astring = [[NSString alloc] init];  
    astring = @"This is a String!";  
    [astring release];  
    NSLog(@"astring:%@",astring);  
      
      
      
    //3、在以上方法中，提升速度:initWithString方法  
      
    NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];  
    NSLog(@"astring:%@",astring);  
    [astring release];  
      
      
      
    //4、用标准c创建字符串:initWithCString方法  
      
    char *Cstring = "This is a String!";  
    NSString *astring = [[NSString alloc] initWithCString:Cstring];  
    NSLog(@"astring:%@",astring);  
    [astring release];  
      
      
      
    //5、创建格式化字符串:占位符（由一个%加一个字符组成）  
      
    int i = 1;  
    int j = 2;  
    NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"%d.This is %i string!",i,j]];  
    NSLog(@"astring:%@",astring);  
    [astring release];  
      
      
      
    //6、创建临时字符串  
      
    NSString *astring;  
    astring = [NSString stringWithCString:"This is a temporary string"];  
    NSLog(@"astring:%@",astring);  
      
      
      
      
    /*----------------从文件读取字符串:initWithContentsOfFile方法----------------*/      
      
    NSString *path = @"astring.text";  
    NSString *astring = [[NSString alloc] initWithContentsOfFile:path];  
    NSLog(@"astring:%@",astring);  
    [astring release];  
      
      
    /*----------------写字符串到文件:writeToFile方法----------------*/      
      
      
    NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];  
    NSLog(@"astring:%@",astring);  
    NSString *path = @"astring.text";      
    [astring writeToFile: path atomically: YES];  
    [astring release];      
      
      
      
      
    /*----------------比较两个字符串----------------*/          
      
    //用C比较:strcmp函数  
      
    char string1[] = "string!";  
    char string2[] = "string!";  
    if(strcmp(string1, string2) = = 0)  
    {  
        NSLog(@"1");  
    }  
      
      
      
    //isEqualToString方法      
    NSString *astring01 = @"This is a String!";  
    NSString *astring02 = @"This is a String!";  
    BOOL result = [astring01 isEqualToString:astring02];  
    NSLog(@"result:%d",result);  
      
      
      
      
    //compare方法(comparer返回的三种值)      
    NSString *astring01 = @"This is a String!";  
    NSString *astring02 = @"This is a String!";      
    BOOL result = [astring01 compare:astring02] = = NSOrderedSame;      
    NSLog(@"result:%d",result);      
    //NSOrderedSame判断两者内容是否相同  
      
      
      
      
    NSString *astring01 = @"This is a String!";  
    NSString *astring02 = @"this is a String!";  
    BOOL result = [astring01 compare:astring02] = = NSOrderedAscending;      
    NSLog(@"result:%d",result);  
    //NSOrderedAscending判断两对象值的大小(按字母顺序进行比较，astring02大于astring01为真)  
      
      
      
    NSString *astring01 = @"this is a String!";  
    NSString *astring02 = @"This is a String!";  
    BOOL result = [astring01 compare:astring02] = = NSOrderedDescending;      
    NSLog(@"result:%d",result);       
    //NSOrderedDescending判断两对象值的大小(按字母顺序进行比较，astring02小于astring01为真)  
      
      
      
    //不考虑大小写比较字符串1  
    NSString *astring01 = @"this is a String!";  
    NSString *astring02 = @"This is a String!";  
    BOOL result = [astring01 caseInsensitiveCompare:astring02] = = NSOrderedSame;      
    NSLog(@"result:%d",result);       
    //NSOrderedDescending判断两对象值的大小(按字母顺序进行比较，astring02小于astring01为真)  
      
      
      
    //不考虑大小写比较字符串2  
    NSString *astring01 = @"this is a String!";  
    NSString *astring02 = @"This is a String!";  
    BOOL result = [astring01 compare:astring02  
                            options:NSCaseInsensitiveSearch | NSNumericSearch] = = NSOrderedSame;      
    NSLog(@"result:%d",result);       
      
    //NSCaseInsensitiveSearch:不区分大小写比较 NSLiteralSearch:进行完全比较，区分大小写 NSNumericSearch:比较字符串的字符个数，而不是字符值。  
      
      
    /*----------------改变字符串的大小写----------------*/      
      
    NSString *string1 = @"A String";   
    NSString *string2 = @"String";   
    NSLog(@"string1:%@",[string1 uppercaseString]);//大写  
    NSLog(@"string2:%@",[string2 lowercaseString]);//小写  
    NSLog(@"string2:%@",[string2 capitalizedString]);//首字母大小  
      
      
    /*----------------在串中搜索子串----------------*/          
      
    NSString *string1 = @"This is a string";  
    NSString *string2 = @"string";  
    NSRange range = [string1 rangeOfString:string2];  
    int location = range.location;  
    int leight = range.length;  
    NSString *astring = [[NSString alloc] initWithString:[NSString stringWithFormat:@"Location:%i,Leight:%i",location,leight]];  
    NSLog(@"astring:%@",astring);  
    [astring release];  
      
      
    /*----------------抽取子串 ----------------*/          
      
    //-substringToIndex: 从字符串的开头一直截取到指定的位置，但不包括该位置的字符  
    NSString *string1 = @"This is a string";  
    NSString *string2 = [string1 substringToIndex:3];  
    NSLog(@"string2:%@",string2);  
      
      
      
      
    //-substringFromIndex: 以指定位置开始（包括指定位置的字符），并包括之后的全部字符  
    NSString *string1 = @"This is a string";  
    NSString *string2 = [string1 substringFromIndex:3];  
    NSLog(@"string2:%@",string2);  
      
      
      
      
    //-substringWithRange: //按照所给出的位置，长度，任意地从字符串中截取子串  
    NSString *string1 = @"This is a string";  
    NSString *string2 = [string1 substringWithRange:NSMakeRange(0, 4)];  
    NSLog(@"string2:%@",string2);  
      
      
    //扩展路径  
      
    NSString *Path = @"~/NSData.txt";  
    NSString *absolutePath = [Path stringByExpandingTildeInPath];  
    NSLog(@"absolutePath:%@",absolutePath);  
    NSLog(@"Path:%@",[absolutePath stringByAbbreviatingWithTildeInPath]);  
      
      
      
    //文件扩展名  
    NSString *Path = @"~/NSData.txt";  
    NSLog(@"Extension:%@",[Path pathExtension]);  
      
      
      
      
    /*******************************************************************************************  
     NSMutableString  
     *******************************************************************************************/      
      
    /*---------------给字符串分配容量----------------*/  
    //stringWithCapacity:  
    NSMutableString *String;  
    String = [NSMutableString stringWithCapacity:40];  
      
      
    /*---------------在已有字符串后面添加字符----------------*/      
      
    //appendString: and appendFormat:  
      
    NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  
    //[String1 appendString:@", I will be adding some character"];  
    [String1 appendFormat:[NSString stringWithFormat:@", I will be adding some character"]];  
    NSLog(@"String1:%@",String1);  
    */  
      
      
    /*--------在已有字符串中按照所给出范围和长度删除字符------*/      
    /*  
     //deleteCharactersInRange:  
     NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  
     [String1 deleteCharactersInRange:NSMakeRange(0, 5)];  
     NSLog(@"String1:%@",String1);  
      
      
      
     /*--------在已有字符串后面在所指定的位置中插入给出的字符串------*/  
      
    //-insertString: atIndex:  
    NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  
    [String1 insertString:@"Hi! " atIndex:0];  
    NSLog(@"String1:%@",String1);  
      
      
      
    /*--------将已有的空符串换成其它的字符串------*/  
      
    //-setString:  
    NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  
    [String1 setString:@"Hello Word!"];  
    NSLog(@"String1:%@",String1);  
      
      
      
    /*--------按照所给出的范围，和字符串替换的原有的字符------*/  
      
    //-setString:  
    NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  
    [String1 replaceCharactersInRange:NSMakeRange(0, 4) withString:@"That"];  
    NSLog(@"String1:%@",String1);  
      
      
      
    /*-------------判断字符串内是否还包含别的字符串(前缀，后缀)-------------*/  
    //01：检查字符串是否以另一个字符串开头- (BOOL) hasPrefix: (NSString *) aString;  
    NSString *String1 = @"NSStringInformation.txt";  
    [String1 hasPrefix:@"NSString"] = = 1 ?  NSLog(@"YES") : NSLog(@"NO");  
    [String1 hasSuffix:@".txt"] = = 1 ?  NSLog(@"YES") : NSLog(@"NO");  
      
    //02：查找字符串某处是否包含其它字符串 - (NSRange) rangeOfString: (NSString *) aString，这一点前面在串中搜索子串用到过;  
      
      
      
    /*******************************************************************************************  
     NSArray  
     *******************************************************************************************/  
      
    /*---------------------------创建数组------------------------------*/  
    //NSArray *array = [[NSArray alloc] initWithObjects:  
    @"One",@"Two",@"Three",@"Four",nil];  
      
    self.dataArray = array;  
    [array release];  
      
    //- (unsigned) Count;数组所包含对象个数；  
    NSLog(@"self.dataArray cound:%d",[self.dataArray count]);  
      
    //- (id) objectAtIndex: (unsigned int) index;获取指定索引处的对象;  
    NSLog(@"self.dataArray cound 2:%@",[self.dataArray objectAtIndex:2]);  
      
      
    /*--------------------------从一个数组拷贝数据到另一数组(可变数级)----------------------------*/      
      
    //arrayWithArray:  
    //NSArray *array1 = [[NSArray alloc] init];  
    NSMutableArray *MutableArray = [[NSMutableArray alloc] init];  
    NSArray *array = [NSArray arrayWithObjects:  
                      @"a",@"b",@"c",nil];  
    NSLog(@"array:%@",array);  
    MutableArray = [NSMutableArray arrayWithArray:array];  
    NSLog(@"MutableArray:%@",MutableArray);  
      
    array1 = [NSArray arrayWithArray:array];  
    NSLog(@"array1:%@",array1);  
      
      
    //Copy  
      
    //id obj;  
    NSMutableArray *newArray = [[NSMutableArray alloc] init];  
    NSArray *oldArray = [NSArray arrayWithObjects:  
                         @"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];  
      
    NSLog(@"oldArray:%@",oldArray);  
    for(int i = 0; i < [oldArray count]; i++)  
    {          
        obj = [[oldArray objectAtIndex:i] copy];  
        [newArray addObject: obj];  
    }  
    //       
    NSLog(@"newArray:%@", newArray);  
    [newArray release];  
      
      
    //快速枚举  
      
    //NSMutableArray *newArray = [[NSMutableArray alloc] init];  
    NSArray *oldArray = [NSArray arrayWithObjects:  
                         @"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];      
    NSLog(@"oldArray:%@",oldArray);  
      
    for(id obj in oldArray)  
    {  
        [newArray addObject: obj];  
    }  
    //       
    NSLog(@"newArray:%@", newArray);  
    [newArray release];      
      
      
    //Deep copy  
      
    //NSMutableArray *newArray = [[NSMutableArray alloc] init];  
    NSArray *oldArray = [NSArray arrayWithObjects:  
                         @"a",@"b",@"c",@"d",@"e",@"f",@"g",@"h",nil];      
    NSLog(@"oldArray:%@",oldArray);      
    newArray = (NSMutableArray*)CFPropertyListCreateDeepCopy(kCFAllocatorDefault, (CFPropertyListRef)oldArray, kCFPropertyListMutableContainers);  
    NSLog(@"newArray:%@", newArray);  
    [newArray release];      
      
      
    //Copy and sort  
      
    //NSMutableArray *newArray = [[NSMutableArray alloc] init];  
    NSArray *oldArray = [NSArray arrayWithObjects:  
                         @"b",@"a",@"e",@"d",@"c",@"f",@"h",@"g",nil];      
    NSLog(@"oldArray:%@",oldArray);  
    NSEnumerator *enumerator;  
    enumerator = [oldArray objectEnumerator];  
    id obj;  
    while(obj = [enumerator nextObject])  
    {  
        [newArray addObject: obj];  
    }  
    [newArray sortUsingSelector:@selector(compare:)];  
    NSLog(@"newArray:%@", newArray);  
    [newArray release];  
      
      
      
    /*---------------------------切分数组------------------------------*/  
      
    //从字符串分割到数组－ componentsSeparatedByString:  
    NSString *string = [[NSString alloc] initWithString:@"One,Two,Three,Four"];  
    NSLog(@"string:%@",string);      
    NSArray *array = [string componentsSeparatedByString:@","];  
    NSLog(@"array:%@",array);  
    [string release];  
      
      
    //从数组合并元素到字符串- componentsJoinedByString:  
    NSArray *array = [[NSArray alloc] initWithObjects:@"One",@"Two",@"Three",@"Four",nil];  
    NSString *string = [array componentsJoinedByString:@","];  
    NSLog(@"string:%@",string);  
      
      
      
    /*******************************************************************************************  
     NSMutableArray  
     *******************************************************************************************/  
    /*---------------给数组分配容量----------------*/  
    //NSArray *array;  
    array = [NSMutableArray arrayWithCapacity:20];  
      
      
      
    /*--------------在数组末尾添加对象----------------*/  
    //- (void) addObject: (id) anObject;  
    //NSMutableArray *array = [NSMutableArray arrayWithObjects:  
    @"One",@"Two",@"Three",nil];  
    [array addObject:@"Four"];  
    NSLog(@"array:%@",array);  
      
      
      
    /*--------------删除数组中指定索引处对象----------------*/      
    //-(void) removeObjectAtIndex: (unsigned) index;      
    //NSMutableArray *array = [NSMutableArray arrayWithObjects:  
    @"One",@"Two",@"Three",nil];  
    [array removeObjectAtIndex:1];  
    NSLog(@"array:%@",array);  
      
      
      
    /*-------------数组枚举---------------*/      
    //- (NSEnumerator *)objectEnumerator;从前向后  
    //NSMutableArray *array = [NSMutableArray arrayWithObjects:  
    @"One",@"Two",@"Three",nil];  
    NSEnumerator *enumerator;  
    enumerator = [array objectEnumerator];  
      
    id thingie;  
    while (thingie = [enumerator nextObject]) {  
        NSLog(@"thingie:%@",thingie);  
    }  
      
      
    //- (NSEnumerator *)reverseObjectEnumerator;从后向前  
    //NSMutableArray *array = [NSMutableArray arrayWithObjects:  
    @"One",@"Two",@"Three",nil];  
    NSEnumerator *enumerator;  
    enumerator = [array reverseObjectEnumerator];  
      
    id object;  
    while (object = [enumerator nextObject]) {  
        NSLog(@"object:%@",object);  
    }  
      
      
    //快速枚举  
    //NSMutableArray *array = [NSMutableArray arrayWithObjects:  
    @"One",@"Two",@"Three",nil];  
    for(NSString *string in array)  
    {  
        NSLog(@"string:%@",string);  
    }  
      
      
      
    /*******************************************************************************************  
     NSDictionary  
     *******************************************************************************************/  
      
    /*------------------------------------创建字典------------------------------------*/  
    //- (id) initWithObjectsAndKeys;  
      
    //NSDictionary *dictionary = [[NSDictionary alloc] initWithObjectsAndKeys:@"One",@"1",@"Two",@"2",@"Three",@"3",nil];  
    NSString *string = [dictionary objectForKey:@"One"];  
    NSLog(@"string:%@",string);  
    NSLog(@"dictionary:%@",dictionary);  
    [dictionary release];  
      
      
    /*******************************************************************************************  
     NSMutableDictionary  
     *******************************************************************************************/  
      
    /*------------------------------------创建可变字典------------------------------------*/      
    //创建  
    NSMutableDictionary *dictionary = [NSMutableDictionary dictionary];  
      
    //添加字典  
    [dictionary setObject:@"One" forKey:@"1"];  
    [dictionary setObject:@"Two" forKey:@"2"];  
    [dictionary setObject:@"Three" forKey:@"3"];  
    [dictionary setObject:@"Four" forKey:@"4"];  
    NSLog(@"dictionary:%@",dictionary);  
      
    //删除指定的字典  
    [dictionary removeObjectForKey:@"3"];  
    NSLog(@"dictionary:%@",dictionary);  
      
      
    /*******************************************************************************************  
     NSValue（对任何对象进行包装）  
     *******************************************************************************************/  
      
    /*--------------------------------将NSRect放入NSArray中------------------------------------*/      
    //将NSRect放入NSArray中  
    NSMutableArray *array = [[NSMutableArray alloc] init];  
    NSValue *value;  
    CGRect rect = CGRectMake(0, 0, 320, 480);      
    value = [NSValue valueWithBytes:&rect objCType:@encode(CGRect)];  
    [array addObject:value];  
    NSLog(@"array:%@",array);  
      
    //从Array中提取  
    value = [array objectAtIndex:0];  
    [value getValue:&rect];  
    NSLog(@"value:%@",value);  
      
      
    /*******************************************************************************************  
     从目录搜索扩展名为jpg的文件  
     *******************************************************************************************/  
      
    //NSFileManager *fileManager = [NSFileManager defaultManager];  
    NSString *home;  
    home = @"../Users/";  
      
    NSDirectoryEnumerator *direnum;  
    direnum = [fileManager enumeratorAtPath: home];  
      
    NSMutableArray *files = [[NSMutableArray alloc] init];  
      
    //枚举  
    NSString *filename;  
    while (filename = [direnum nextObject]) {  
        if([[filename pathExtension] hasSuffix:@"jpg"]){  
            [files addObject:filename];  
        }  
    }  
      
    //快速枚举  
    //for(NSString *filename in direnum)  
    //{  
    //    if([[filename pathExtension] isEqualToString:@"jpg"]){  
    //        [files addObject:filename];  
    //    }  
    //}  
    NSLog(@"files:%@",files);  
      
    //枚举  
    NSEnumerator *filenum;  
    filenum = [files objectEnumerator];  
    while (filename = [filenum nextObject]) {  
        NSLog(@"filename:%@",filename);  
    }  
      
    //快速枚举  
    //for(id object in files)  
    //{  
    //    NSLog(@"object:%@",object);  
    //}  







    #import <Foundation/Foundation.h>  
      
    int main (int argc, const char * argv[]) {  
        NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];  
        //创建字符串  
        NSString *height;  
        /**类方法： 
         +(id) stringWithFormat: (NSString *) format,... 
         通过格式字符串和参数来创建NSString 
         省略号（。。。）：可以接受多个以逗号分割的参数。 
         这声明方法时添加加号（＋），那么这个方法为类方法，不需要创建实例就可以调用，通常用于创建心的实例，我们称用来创建新对象的类方法为工厂方法。 
         －－－－－－－－－－－－－－－－－－－ 
         objective－c运行时生成一个类的时候，它会创建一个代表该类的类对象。类对象包含了指向超类的指针，类名，和指向类方法列表的指针。类对象还包含一个long型数据，为新创建的类实例对象指定大小（以字节为单位） 
          
         类方法可以用来访问全局数据。 
          
         实例方法要用前导减号（－）来开始声明 
          
         */  
          
        height=[NSString stringWithFormat:@"you heigh is %d feet,%d inches",5,11];  
        NSLog(height);  
        //length 返回字符串中字符的个数。－（unsigned int) length;  
        if([height length]>5){  
            NSLog(@"height length ------");  
        }  
          
        //字符串比较  
        /** 
         isEqualToString :可以用来比较接收方和当作参数传递来的字符串的内容是否相同，返回yes和no 
         */  
        NSString *thing1=@"hello";  
        NSString *thing2=[[NSString alloc] initWithString:@"hello"];  
        if([thing1 isEqualToString:thing2]){  
            NSLog(@"they are same");      
        }  
        /** 
         ==:只判断指针数值，而不是它们所指向的内容 
         */  
        if(thing1==thing2){  
            NSLog(@"== same");  
        }  
          
        /* 
         compare:比较两个字符串。区分大小写 
         compare将接收对象和传递来的字符串逐个字符的进行比较，它返回一个NSComparisonResult(枚举类型)来显示结果。 
         typedef enum _NSComparisonResult{ 
         NSOrderedAscending=-1; 
         NSOrderedsame; 
         NSOrderedDescending; 
         } NSComparisonResult; 
         */  
        [thing1 compare:thing2];  
        if(NSOrderedSame==[thing1 compare:thing2]){  
            NSLog(@"compare same");   
        }  
          
        //compare：options:   
        /*** 
         -(NSComparisonResult) compare:(NSString *) string  
         options:(unsinged) mask; 
          
         options 是一个位掩码，可以使用|添加选项标记 
         选项： 
         NSCaseInsensitiveSearch:不区分大小写字符 
         NSLiteralSearch:进行完全比较，区分大小写 
         NSNumbericSearch:比较字符串的字符个数，而不是字符值 
         */  
        if([thing1 compare:thing2 options:NSCaseInsensitiveSearch|  
             NSNumericSearch]==NSOrderedSame){  
            NSLog(@"they match");  
        }  
          
        /** 
         以某个字符串开始或结尾 
         -(BOOL) hasPrefix:(NSString *) aString; 
         -(BOOL) hasSuffix:(NSString *) aString; 
         */  
        NSString *fileName=@"aabbbcc";  
        if([fileName hasPrefix:@"aa"]){  
            NSLog(@"begin with aa");  
        }  
          
        if([fileName hasSuffix:@"cc"]){  
            NSLog(@"end with cc");  
        }  
          
        //NSMutableString 可变字符串  
        //SString 是不可变的，一旦NSString 被创建了，我们就不能改变它。  
          
        //+(id) stringWithCapacity:(unsinged) capacity; capacity:是给NSMutableString的一个建议，字符串的大小并不局限于所提供的大小，这个容量仅是个最优值。  
          
        NSMutableString *str=[NSMutableString stringWithCapacity:40];  
        [str appendFormat:@"sdfsdf%d",5];  
        [str appendString:@"ssssssss"];  
        NSLog(str);  
          
        //删除字符串  
        //-(void) deleteCharactersInRange:(NSRange) range;  
          
        NSMutableString *ms;  
        ms=[NSMutableString stringWithCapacity:50];  
        [ms appendString:@"aabbccdd"];  
        NSRange range;  
        range=[ms rangeOfString:@"cc"];  
        [ms deleteCharactersInRange:range];  
        NSLog(ms);  
          
        //与实例方法一样，继承对类方法也同样适用  
          
        //------------------集合－－－－－－－－－－－－－－  
        //NSArray ,NSDictionary  
        /** 
         NSArray 是一个cocoa类，用来存储对象的有序列表。 
        NSArray有两个限制：1，它只能存储objective－c的对象，而不能存储c语言中的基本数据类型如int，float，enum，struct，或者nsarray中的随机指针。2，不能这nsarray中存储nil 
          
         类方法： 
         arrayWithObjects:创建一个新的nsarray。发送一个以逗号分割的对象列表，这列表结尾添加nil代表列表结束，（这就是不能这nsarray中存储nil的原因） 
          
         */  
        NSArray *array=[NSArray arrayWithObjects:@"aa",@"bb",@"cc",nil];  
          
        //-(unsigned) count; 取得包含对象的个数  
        //-(id) objectAtIndex:(unsigned int) index; 取得索引位置的对象  
          
        int i;  
        for (i=0; i<[array count]; i++) {  
            NSLog(@"index %d has %@",i,[array objectAtIndex:i]);  
        }  
          
        //------------切分数组  
        //-componentsSeparatedByString:  
        NSString *ns=@"sdf,dsfs,dfd,fdf,df,dd";  
        NSArray *comArr=[ns componentsSeparatedByString:@","];  
        for(int i=0;i<[comArr count];i++){  
            NSLog(@"componentsSeparatedByString===%@",[comArr objectAtIndex:i]);  
        }  
          
        //componentJoinedByString: 合并nsarray中的元素来创建字符串  
        NSString *joinedStr=[comArr componentsJoinedByString:@"-->"];  
        NSLog(@"joined---= %@",joinedStr);  
          
        //可变数组  
        NSMutableArray *mutableArr=[NSMutableArray arrayWithCapacity:40];  
        [mutableArr addObject:@"aa"];  
        [mutableArr addObject:@"bb"];  
        [mutableArr addObject:@"cc"];  
        [mutableArr addObject:@"dd"];  
          
        for(int i=0;i<[mutableArr count];i++){  
            NSLog(@"mutableArr==%@",[mutableArr objectAtIndex:i]);  
        }  
          
        //-----  -(void) removeObjectAtIndex:(unsinged) index; 删除指定索引的对象,  
        //删除一个对象之后，数组中并没有留下漏洞，被删除对象后面的数组元素的哦被前移来填补空缺  
        [mutableArr removeObjectAtIndex:2];  
        for(int i=0;i<[mutableArr count];i++){  
            NSLog(@"removeObjectAtIndex == %@",[mutableArr objectAtIndex:i]);  
        }  
          
        //枚举  
        //NSEnumerator ,它是cocoa用来描述这种集合迭代运输的方法  
        //-(NSEnumerator *) objectEnumerator;  
        NSEnumerator *enumerator=[mutableArr objectEnumerator];  
        id thingie;  
        while(thingie=[enumerator nextObject]){  
            NSLog(@"i found %@",thingie);  
        }  
          
        //快速枚举  
        for(NSString *string in mutableArr){  
            NSLog(@"for in == %@",string);  
        }  
          
        //NSDictionary 字典  
        /* 
         NSDictionary 是在给定的关键字（通常是一个NSString字符串）下存储一个数值（可以是任何类型的对象）。然后你可以用这个关键字来查找相应的数值。 
         NSDictionary 是键查询的优化存储方式。它可以立即找出要查询的数据，而不需要遍历整个数组进行查找。 
          
         ＋（id) dictionaryWithObjectAndKeys:(id) firstObject,....; 
         该方法接收对象和关键字交替出现的系列，以nil值作为终止符号。 
         **/  
        NSDictionary *dic=[NSDictionary dictionaryWithObjectsAndKeys:@"aaa",@"a",@"bbb",@"b",nil];  
        NSString *dicStr=[dic objectForKey:@"a"];  
        if([dicStr isEqualToString:@"aaa"]){  
            NSLog(@"------------00000000000000000");  
        }  
          
        //可变字典  
        NSMutableDictionary *mutableDic=[NSMutableDictionary dictionaryWithCapacity:50];  
        [mutableDic setObject:@"1111" forKey:@"1"];  
        [mutableDic setObject:@"222" forKey:@"2"];  
          
        //删除 -(void) removeObjectForKe:(id) key;  
        [mutableDic removeObjectForKey:@"2"];  
          
        NSArray *keyArr=[mutableDic allKeys];  
        for(NSString *str in keyArr){  
            NSLog(@"key== %@",str);  
            NSLog(@"value== %@",[mutableDic objectForKey:str]);  
        }  
          
          
        //各种数值，NSNumber NSValue  
        /* 
         cocoa 提供了NSNumber类来包装基本数据类型 
         +(NSNumber *) numberWithChar:(char) value; 
         +(NSNumber *) numberWithInt:(int) value; 
         +(NSNumber *) numberWithFloat:(float) value; 
         +(NSNumber *) numberWthiBool:(BOOL) value; 
          
         -(char) charValue; 
         -(int) intVlaue; 
         -(float) floatValue; 
         -(BOOL) boolValue; 
         -(NSString *) stringValue; 
          
          
         **/  
        NSNumber *number;  
        number=[NSNumber numberWithInt:3];  
        [mutableDic setObject:number forKey:@"int"];  
          
        int num=[[mutableDic objectForKey:@"int"] intValue];  
        NSLog(@"int object value== %d",num);  
          
          
        //NSValue .NSNumber实际上是NSValue的子类，NSValue可以包装任意值  
          
        /** 
         +(NSValue *) valueWithBytes:(const void *) value objCType:(const char *) type; 
         传递的参数是你想要包装的数值的地址，通常，得到的是你想要存储的变量的地址（在c语言里适用操作符 & ），你也可以提供一个描述这个数据类型的字符串，通常用来说明struct中实体的类型和大小。你不用自己写代码 
         来生成这个字符串，@encode编译器指令可以接受数据类型的名称并为你生成合适的字符串 
         */  
        NSRect rect= NSMakeRect(1, 2, 30, 40);  
          
        NSValue *value;  
        value=[NSValue valueWithBytes:&rect objCType:@encode(NSRect)];  
        NSMutableArray *mr=[NSMutableArray arrayWithCapacity:50];  
        [mr addObject:value];  
           
        //getValue 提取数据  
        /** 
         -(void) getValue:(void *) value; 要传递的是存储这个数值的变量的地址 
         */  
          
        /*** 
        value=[mr objectAtIndex:0]; 
          
        NSRect r; 
        NSLog(@"00000 ===%@",r); 
        [value getValue:&r]; 
        NSLog(@"111== %@",r); 
        */  
          
        /** 
         +(NSValue *) valueWithPoint:(NSPoint) point; 
         +(NSValue *) valueWithSize:(NSSize) size; 
         +(NSValue *) valueWithRect:(NSRect) rect; 
          
          
          
         -(NSPoint) pointValue; 
         -(NSSize) sizeValue; 
         -(NSRect) rectValue; 
          
         */  
          
        //NSNull   
        /* 
         *+(NSNull *) null;  
        */  
        [mutableDic setObject:[NSNull null] forKey:@"fax"];  
        id fax;  
        fax=[mutableDic objectForKey:@"fax"];  
        if(fax==[NSNull null]){  
            NSLog(@"pppppppppppppppppp");  
        }  
          
        [pool drain];  
        return 0;  
    }