objective-c NSString 常用操作

//1、创建常量字符串。

NSString*astring=@"ThisisaString!";

//2、创建空字符串,给予赋值。

NSString*astring=[[NSStringalloc]init];

astring=@"ThisisaString!";

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

[astringrelease];

//3、在以上方法中,提升速度:initWithString方法

NSString*astring=[[NSStringalloc]initWithString:@"ThisisaString!"];

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

[astringrelease];

//4、用标准c创建字符串:initWithCString方法

char*Cstring="ThisisaString!";

NSString*astring=[[NSStringalloc]initWithCString:Cstring];

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

[astringrelease];

//5、创建格式化字符串:占位符(由一个%加一个字符组成)

inti=1;

intj=2;

NSString*astring=[[NSStringalloc]initWithString:[NSStringstringWithFormat:@"%d.Thisis%istring!",i,j]];

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

[astringrelease];

//6、创建临时字符串

NSString*astring;

astring=[NSStringstringWithCString:"Thisisatemporarystring"];

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

NSString*path=@"astring.text";

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

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

[astringrelease];

NSString*astring=[[NSStringalloc]initWithString:@"ThisisaString!"];

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

NSString*path=@"astring.text";

[astringwriteToFile:pathatomically:YES];

[astringrelease];

//用C比较:strcmp函数

charstring1[]="string!";

charstring2[]="string!";

if(strcmp(string1,string2)==0)

{

NSLog(@"1");

}

//isEqualToString方法

NSString*astring01=@"ThisisaString!";

NSString*astring02=@"ThisisaString!";

BOOLresult=[astring01isEqualToString:astring02];

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

//compare方法(comparer返回的三种值)

NSString*astring01=@"ThisisaString!";

NSString*astring02=@"ThisisaString!";

BOOLresult=[astring01compare:astring02]==NSOrderedSame;

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

//NSOrderedSame判断两者内容是否相同

NSString*astring01=@"ThisisaString!";

NSString*astring02=@"thisisaString!";

BOOLresult=[astring01compare: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=@"thisisaString!";

NSString*astring02=@"ThisisaString!";

BOOLresult=[astring01compare: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=@"thisisaString!";

NSString*astring02=@"ThisisaString!";

BOOLresult=[astring01caseInsensitiveCompare: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)

//如何判断字符串为空

NSString*urlString=[urlInputstringValue];

if(!urlString){

NSLog(@”NOINPUT.”);

}else{

if([urlStringlength]==0){

NSLog(@”NOINPUT.”);

}else{

}

}

}

ConvertNSStringtoint

1NSString*aNumberString=@"123";

2inti=[aNumberStringintValue];

ConvertinttoNSString

1intaNumber=123;

2NSString*aString=[NSStringstringWithFormat:@"%d",aNumber];

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