iphone 字符串转换积累中

NSString 转 char*

-(int)xTransferNSString2Char:(NSString*)str xhdtk: (char*)dchar
{   
    int length = [str length];   
    int index = 0;
    for (int i = 0; i < length; ++i)
    {
        if (i > 259)
        {
            break;
        }
        NSRange range = NSMakeRange(i, 1);
        NSString *subString = [str substringWithRange:range];
        const char* cString = [subString UTF8String];
        if (strlen(cString) == 3)
        {
            // NSLog(@"hanzi\n");
            memcpy(dchar + index, cString, 3);
            index = index + 3;           
        }
        else
        {           
            char *temp = (char*)[subString cStringUsingEncoding:NSASCIIStringEncoding];            
            memcpy(dchar + index, temp, 1);
            index = index + 1;
        }
       
    }
    return index;
}

 

NSString *str;

char *temp = (char*)[str cStringUsingEncoding:NSASCIIStringEncoding];

 

 

(2)

NSString *str;

char *temp = (char*)[str cStringUsingEncoding:NSASCIIStringEncoding];

 

判断是否为空的方法。

NSString *string;

if ([string length] = = 0 || string = = nil || [string isEqualToString:@””] )

{

//dosomething

}

 

NSString 之间

NSString *str1;

NSString *str2;

...

NSString* str3= [NSString stringWithFormat:@%@%@,str1,str2];

 

 

以下网上下载

NSString,NSMutableString,NSArray,NSMutableArray,NSDictionary,NSMutableDictionary和NSValue用法汇总

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