Object-c中对于NSSting类的方法总结

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);

7、判断字符串为空

　　NSString *urlString = [urlInput stringValue];

if (!urlString) {

NSLog( @”NO INPUT.” );

}

if ([urlString length] == 0 ) {

NSLog( @”NO INPUT.” );

}

8、是否以”test”开头;是否以”.move”结尾;

　　NSString *fileName = @”test.move”;

　　if ([fileName hasPrefix:@"test"]) {

　　NSLog(@”has Test String !”);

　　}else{

　　NSLog(@”don’t have Test”);

　　}

　　[fileName hasSuffix:@".move"] NSLog(@”Yes it got a .Mov in its end”):NSLog(@”no it has no .mov string”);

9、比较两个字符串:

　　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。

10、声明一个可变字符;长度是40个字符;

　　NSMutableString *myMutableString;

　　myMutableString = [NSMutableString stringWithCapacity:40];

　　NSString *myName = @”Leo”;

　　[myMutableString appendString:@"Hello ,there"];

　　[myMutableString appendFormat:@" i am %@",myName];

　　NSLog(@”this is NSMutableString: %@”,myMutableString);

　　//this is NSMutableString: Hello ,there i am Leo;

11、修改可变字符;先声明一个可变字符 myFriend;长度30;

　　NSMutableString *myGirlFriend;

　　myGirlFriend = [NSMutableString stringWithCapacity:30];

　　//然后给字符加入一些内容;

　　[myGirlFriend appendString:@"Here are my GF:Carol Sophia Ashley Helen and Yoyo"];

　　NSLog(@”%@”,myGirlFriend);

　　//声名一个变动范围(NSRange);

　　NSRange joneRange;

　　joneRange = [myGirlFriend rangeOfString:@"Helen "];

　　//下面:就是从myFriend字符中配对,如果有相等的内容就删除了;

　　[myGirlFriend deleteCharactersInRange:joneRange];

　　NSLog(@”%@”,myGirlFriend);

12、在一个字符串后面附加一个新的字符串

　　NSString *a = @"a";

　　NSString *b = [a stringByAppendingString:@"b"];//b变量的值为“ab”

13、字符串转换整数值

　　NSString *age = @"36";

　　if([age intValue]>35){

　　}

14、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];1

15、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];

16、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

17、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];

18、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);

19、扩展路径

NSString *Path = @"~/NSData.txt";

NSString *absolutePath = [Path stringByExpandingTildeInPath];

NSLog(@"absolutePath:%@",absolutePath);

NSLog(@"Path:%@",[absolutePath stringByAbbreviatingWithTildeInPath]);

20、文件扩展名

NSString *Path = @"~/NSData.txt";

NSLog(@"Extension:%@",[Path pathExtension]);

21、在已有字符串后面添加字符

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);

22、在已有字符串中按照所给出范围和长度删除字符

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

[String1 deleteCharactersInRange:NSMakeRange(0, 5)];

NSLog(@"String1:%@",String1);

23、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);

24、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);

25、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);

26、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;