iphone开发NSString字符串常用方法

//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);

//

NSString *astring = [[NSString alloc] init];

NSLog(@"0x%.8x", astring);

astring=@"This is a String!";

NSLog(@"0x%.8x", astring);

[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);

//}