iOS NSString的常用用法

iOS NSString的常用用法

 

//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。
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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);
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//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
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char *Cstring = "This is a String!";
 
NSString *astring = [[NSString alloc] initWithCString:Cstring];
 
NSLog(@"astring:%@",astring);
 
[astring release];
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//5、创建格式化字符串:占位符（由一个%加一个字符组成）
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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];
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//6、创建临时字符串
NSString *astring;
 
astring = [NSString stringWithCString:"This is a temporary string"];
 
NSLog(@"astring:%@",astring);
 
//7、从文件创建字符串
NSString *path = [[NSBundlemainBundle] pathForResource:@"astring.text"ofType:nil];
NSString *astring = [[NSString alloc] initWithContentsOfFile:path];
NSLog(@"astring:%@",astring);
[astring release];
 
//8、用字符串创建字符串，并写入到文件 
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NSString *astring = [[NSString alloc] initWithString:@"This is a String!"];
 
NSLog(@"astring:%@",astring);
 
NSString *path = @"astring.text";   
 
[astring writeToFile: path atomically: YES];
 
[astring release]; 
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注：此路径path只只是示意，真实路径并非如此
 
//9、用C比较:strcmp函数
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char string1[] = "string!";
 
char string2[] = "string!";
 
if(strcmp(string1, string2) == 0)
{
 
    NSLog(@"1");
 
}
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//10、isEqualToString方法   
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NSString *astring01 = @"This is a String!";
 
NSString *astring02 = @"This is a String!";
 
BOOL result = [astring01 isEqualToString:astring02];
 
NSLog(@"result:%d",result);
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//11、compare方法(comparer返回的三种值)   
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//
NSString *astring01 = @"This is a String!";
 
NSString *astring02 = @"This is a String!";   
 
BOOL result = [astring01 compare:astring02] == NSOrderedSame;    //NSOrderedSame判断两者内容是否相同
 
NSLog(@"result:%d",result);   
 
//
NSString *astring01 = @"This is a String!";
 
NSString *astring02 = @"this is a String!";
 
BOOL result = [astring01 compare:astring02] == NSOrderedAscending;    //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)
 
NSLog(@"result:%d",result);

//
NSString *astring01 = @"this is a String!";
 
NSString *astring02 = @"This is a String!";
 
BOOL result = [astring01 compare:astring02] == NSOrderedDescending;    //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)
 
NSLog(@"result:%d",result);    
 
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//12、不考虑大小写比较字符串
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//1.
NSString *astring01 = @"this is a String!";
 
NSString *astring02 = @"This is a String!";
 
BOOL result = [astring01 caseInsensitiveCompare:astring02] == NSOrderedSame;    //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)

NSLog(@"result:%d",result);

//2.
NSString *astring01 = @"this is a String!";
 
NSString *astring02 = @"This is a String!";
 
BOOL result = [astring01 compare:astring02
 
options:NSCaseInsensitiveSearch | NSNumericSearch] == NSOrderedSame;    //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。
 
NSLog(@"result:%d",result);
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//13、输出大写或者小写字符串
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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
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//14、-rangeOfString: //查找字符串某处是否包含其它字符串
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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];
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//15、-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);
 
//16、-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);
 
//17、-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);
 
//18、-stringWithCapacity: //按照固定长度生成空字符串
NSMutableString *String;
 
String = [NSMutableString stringWithCapacity:40];
 
//19、-appendString: and -appendFormat: //把一个字符串接在另一个字符串的末尾
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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);
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//20、-insertString: atIndex: //在指定位置插入字符串
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
 
[String1 insertString:@"Hi! " atIndex:0];
 
NSLog(@"String1:%@",String1);
 
//21、-setString:
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
 
[String1 setString:@"Hello Word!"];
 
NSLog(@"String1:%@",String1);
 
//22、-replaceCharactersInRange: withString: //用指定字符串替换字符串中某指定位置、长度的字符串
NSMutableString *String1 = [[NSMutableString alloc] initWithString:@"This is a NSMutableString"];
 
[String1 replaceCharactersInRange:NSMakeRange(0, 4) withString:@"That"];
 
NSLog(@"String1:%@",String1);
 
//23、-hasPrefix: //检查字符串是否以另一个字符串开头
NSString *String1 = @"NSStringInformation.txt";
 
[String1 hasPrefix:@"NSString"] = = 1 ?  NSLog(@"YES") : NSLog(@"NO");
 
[String1 hasSuffix:@".txt"] = = 1 ?  NSLog(@"YES") : NSLog(@"NO");
 
//24、扩展路径
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NSString *Path = @"~/NSData.txt";
 
NSString *absolutePath = [Path stringByExpandingTildeInPath];
 
NSLog(@"absolutePath:%@",absolutePath);
 
NSLog(@"Path:%@",[absolutePath stringByAbbreviatingWithTildeInPath]);
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//25、文件扩展名
NSString *Path = @"~/NSData.txt";
 
NSLog(@"Extension:%@",[Path pathExtension]);