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字符串的一些用法

//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;  

 //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      

    //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);  

    NSString *path = @"astring.text";  

    NSString *astring = [[NSString alloc] initWithContentsOfFile:path];  

    NSLog(@"astring:%@",astring);  

    [astring release];  

    NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];  

    NSLog(@"astring:%@",astring);  

    NSString *path = @"astring.text";      

    [astring writeToFile: path atomically: YES];  

    [astring release];      

    //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。  

    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  

    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];  

    //-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]);  

    //stringWithCapacity:  

    NSMutableString *String;  

    String = [NSMutableString stringWithCapacity:40];  

    //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);  

    */  

    //-insertString: atIndex:  

    NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  

    [String1 insertString:@"Hi! " atIndex:0];  

    NSLog(@"String1:%@",String1);  

    //-setString:  

    NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  

    [String1 setString:@"Hello Word!"];  

    NSLog(@"String1:%@",String1);  

    //-setString:  

    NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];  

    [String1 replaceCharactersInRange:NSMakeRange(0, 4) withString:@"That"];  

    NSLog(@"String1:%@",String1);  

    //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 *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]);  

    //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];  

    //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);  

    //NSArray *array;  

    array = [NSMutableArray arrayWithCapacity:20];  

    //- (void) addObject: (id) anObject;  

    //NSMutableArray *array = [NSMutableArray arrayWithObjects:  

    @"One",@"Two",@"Three",nil];  

    [array addObject:@"Four"];  

    NSLog(@"array:%@",array);  

    //-(void) removeObjectAtIndex: (unsigned) index;      

    //NSMutableArray *array = [NSMutableArray arrayWithObjects:  

    @"One",@"Two",@"Three",nil];  

    [array removeObjectAtIndex:1];  

    NSLog(@"array:%@",array);  

    //- (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);  

    }  

    //- (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];  

    //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);  

    //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);  

    //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;  

        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  

        NSString *[email protected]"hello";  

        NSString *thing2=[[NSString alloc] initWithString:@"hello"];  

        if([thing1 isEqualToString:thing2]){  

            NSLog(@"they are same");      

        }  

        if(thing1==thing2){  

            NSLog(@"== same");  

        }  

        [thing1 compare:thing2];  

        if(NSOrderedSame==[thing1 compare:thing2]){  

            NSLog(@"compare same");   

        }  

        //compare:options:   

        if([thing1 compare:thing2 options:NSCaseInsensitiveSearch|  

             NSNumericSearch]==NSOrderedSame){  

            NSLog(@"they match");  

        }  

        NSString *[email protected]"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 *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 *[email protected]"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 *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  

        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  

        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  

        //NSNull   

        [mutableDic setObject:[NSNull null] forKey:@"fax"];  

        id fax;  

        fax=[mutableDic objectForKey:@"fax"];  

        if(fax==[NSNull null]){  

            NSLog(@"pppppppppppppppppp");  

        }  

        [pool drain];  

        return 0;  

    }