NSString的属性相关

1. NSData 与 NSString
NSData－> NSString
NSString *aString = [[NSString alloc] initWithData:adataencoding:NSUTF8StringEncoding];

NSString－>NSData
NSString *aString = @"1234abcd";
NSData *aData = [aString dataUsingEncoding: NSUTF8StringEncoding];

2.NSData 与 Byte
NSData－> Byte数组
NSString *testString = @"1234567890";
NSData *testData = [testString dataUsingEncoding: NSUTF8StringEncoding];
Byte *testByte = (Byte *)[testData bytes];
for(int i=0;i<[testData length];i++)
printf("testByte = %d\n",testByte[i]);

Byte数组－> NSData
Byte byte[] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23};
NSData *adata = [[NSData alloc] initWithBytes:byte length:24];

Byte数组－>16进制数
Byte *bytes = (Byte *)[aData bytes];
NSString *hexStr=@"";
for(int i=0;i<[encryData length];i++)
{
NSString *newHexStr = [NSString stringWithFormat:@"%x",bytes[i]&0xff];///16进制数
if([newHexStr length]==1)
hexStr = [NSString stringWithFormat:@"%@0%@",hexStr,newHexStr];
else
hexStr = [NSString stringWithFormat:@"%@%@",hexStr,newHexStr];
}
NSLog(@"bytes 的16进制数为:%@",hexStr);

16进制数－>Byte数组
/ 将16进制数据转化成Byte 数组
NSString *hexString = @"3e435fab9c34891f"; //16进制字符串
int j=0;
Byte bytes[128];  ///3ds key的Byte 数组， 128位
for(int i=0;i<[hexString length];i++)
{
int int_ch;  /// 两位16进制数转化后的10进制数

unichar hex_char1 = [hexString characterAtIndex:i]; 两位16进制数中的第一位(高位*16)
int int_ch1;
if(hex_char1 >= '0' && hex_char1 <='9')
int_ch1 = (hex_char1-48)*16;    0 的Ascll - 48
else if(hex_char1 >= 'A' && hex_char1 <='F')
int_ch1 = (hex_char1-55)*16; A 的Ascll - 65
else
int_ch1 = (hex_char1-87)*16; a 的Ascll - 97
i++;

unichar hex_char2 = [hexString characterAtIndex:i]; ///两位16进制数中的第二位(低位)
int int_ch2;
if(hex_char2 >= '0' && hex_char2 <='9')
int_ch2 = (hex_char2-48); 0 的Ascll - 48
else if(hex_char1 >= 'A' && hex_char1 <='F')
int_ch2 = hex_char2-55; A 的Ascll - 65
else
int_ch2 = hex_char2-87; a 的Ascll - 97

int_ch = int_ch1+int_ch2;
NSLog(@"int_ch=%d",int_ch);
bytes[j] = int_ch;  ///将转化后的数放入Byte数组里
j++;
}
NSData *newData = [[NSData alloc] initWithBytes:bytes length:128];
NSLog(@"newData=%@",newData);

3. NSData 与 UIImage
NSData－>UIImage
UIImage *aimage = [UIImage imageWithData: imageData];

//例：从本地文件沙盒中取图片并转换为NSData
NSString *path = [[NSBundle mainBundle] bundlePath];
NSString *name = [NSString stringWithFormat:@"ceshi.png"];
NSString *finalPath = [path stringByAppendingPathComponent:name];
NSData *imageData = [NSData dataWithContentsOfFile: finalPath];
UIImage *aimage = [UIImage imageWithData: imageData];

UIImage－> NSData
NSData *imageData = UIImagePNGRepresentation(aimae);


/*******************************************************************************************
     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!";
    NSLog(@"astring:%@",astring);
  [astring release];




    //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------------------------------*/

   1.

   //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);

    2.

    NSString *a ="/pubic/evdaily.nsf/vwtrymaindocid/8E88469482579180035442A/$file/测试帐号及信息22.docx";

    NSRange range = [arangeOfString:@"$file/"];//获取$file/的位置

    NSString *b = [a substringFromIndex:range.location +  range.length];//开始截取

    NSLog(@"\n b: %@",b);

    /*******************************************************************************************
     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);
    }

参考：

http://qun.qq.com/air/#186700354/share

http://www.cnblogs.com/85538649/archive/2011/11/21/2256868.html

http://www.wezu.net/blog/archives/86