NSString、NSMutableString基本使用

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NSString事实上是一个对象类型。NSString是NSObject（Cocoa Foundation的基础对象）的子类

一、NSString的创建

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、创建暂时字符串
NSString *astring;
astring = [NSString stringWithCString:"This is a temporary string"];
NSLog(@"astring:%@",astring);

7、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];

8、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];

二、字符串的比較

1、用C比較:strcmp函数
char string1[] = "string!";
char string2[] = "string!";
if(strcmp(string1, string2) = = 0)
{
NSLog(@"1");
}

2、isEqualToString方法    
NSString *astring01 = @"This is a String!";
NSString *astring02 = @"This is a String!";
BOOL result = [astring01 isEqualToString:astring02];
NSLog(@"result:%d",result);

3、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推断两者内容是否同样

NSString *astring01 = @"This is a String!";
NSString *astring02 = @"this is a String!";
BOOL result = [astring01 compare:astring02] = = NSOrderedAscending;    
NSLog(@"result:%d",result);
//NSOrderedAscending推断两对象值的大小(按字母顺序进行比較。astring02大于astring01为真)

不考虑大写和小写比較字符串
NSString *astring01 = @"this is a String!";
NSString *astring02 = @"This is a String!";
BOOL result = [astring01 caseInsensitiveCompare:astring02] = = NSOrderedSame;    
NSLog(@"result:%d",result);     
//NSOrderedDescending推断两对象值的大小(按字母顺序进行比較，astring02小于astring01为真)

不考虑大写和小写比較字符串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);     
P.S : NSCaseInsensitiveSearch:不区分大写和小写比較 NSLiteralSearch:进行全然比較。区分大写和小写 NSNumericSearch:比較字符串的字符个数，而不是字符值。

三、改写字符串

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

四、搜索字符串

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];

五、字符串的截取

1.-substringToIndex: 从字符串的开头一直截取到指定的位置，但不包含该位置的字符
NSString *string1 = @"This is a string";
NSString *string2 = [string1 substringToIndex:3];
NSLog(@"string2:%@",string2);

2.-substringFromIndex: 以指定位置開始（包含指定位置的字符），并包含之后的所有字符
NSString *string1 = @"This is a string";
NSString *string2 = [string1 substringFromIndex:3];
NSLog(@"string2:%@",string2);

3.-substringWithRange: //依照所给出的位置，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);

4.截取NSString最后一位符号后的东西

方法1.

NSString *str = @"/Users/yangiori/Library/Application Support/iPhone Simulator/5.1/Applicati*****/8724956B-407E-4ACD-BBA6-95C7D033C33D/Documents/content/chapters/8";
NSString *temp1 = [[str componentsSeparatedByString:@"/"] lastObject];
NSLog(@"%@",temp1);

结果：8

方法2.

NSString *str = @"/Users/yangiori/Library/Application Support/iPhone Simulator/5.1/Applicati*****/8724956B-407E-4ACD-BBA6-95C7D033C33D/Documents/content/chapters/8";

NSString *temp2 = [str substringFromIndex:[str length]-1];

NSLog(@"%@",temp2);

结果：8

5.从指定位置截取字符串

NSString * str =[NSString stringWithFormat:@"********************Documents/image%i.jpg",2];

NSRange range = [str rangeOfString:@"Documents"];

NSString * result = [str substringFromIndex:range.location];

NSLog(@"%@",result);

六、其他操作

1.扩展路径
NSString *Path = @"~/NSData.txt";
NSString *absolutePath = [Path stringByExpandingTildeInPath];
NSLog(@"absolutePath:%@",absolutePath);
NSLog(@"Path:%@",[absolutePath stringByAbbreviatingWithTildeInPath]);

2.文件扩展名
NSString *Path = @"~/NSData.txt";
NSLog(@"Extension:%@",[Path pathExtension]);

NSMutableString

基本使用方法

1.给字符串分配容量

stringWithCapacity:
NSMutableString *String;
String = [NSMutableString stringWithCapacity:40];

2.在已有字符串后面加入字符

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);

3.在已有字符串中依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);

4.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);

5.将已有的空符串换成其他的字符串

-setString:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
[String1 setString:@"Hello Word!"];
NSLog(@"String1:%@",String1);

6.依照所给出的范围。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);

7.推断字符串内是否还包含别的字符串(前缀。后缀)

01：检查字符串是否以还有一个字符串开头- (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他字符串 - (NSRange) rangeOfString: (NSString *) aString，这一点前面在串中搜索子串用到过;

郝萌主倾心贡献。尊重作者的劳动成果，请勿转载。

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Cocos2d-X源代码下载：点我传送

游戏官方下载：http://dwz.cn/RwTjl

游戏视频预览：http://dwz.cn/RzHHd

游戏开发博客：http://dwz.cn/RzJzI

游戏源代码传送：http://dwz.cn/Nret1