[iOS 개발]-NString 의 확장 사용

첫째:기본 데이터 형식 과 문자열 변환
//기본 데이터 형식(int float,double char)

1）      —>NSString       
//1.int        
int a = 88;
NSString * str1 = [NSString stringWithFormat:@"%d",a];
       
//2.float -> NSString
float f = 0.8;
NSString * str3 = [NSString stringWithFormat:@"%.1f",f];

//3.double - >NSstring
 double d = 66.2222;
 NSString * str4 = [NSString stringWithFormat:@"%.4f",d];
       
//4.char - > NSString
char c = ‘b';
NSString * str5 = [NSString stringWithFormat:@"%c",c];
       
2）NSString-—>           

//5.NSString -> int
 NSString * str6 = @"1";
int i1 = [str6 intValue];
       
//5.NSString -> float
NSString * str7 = @“8.8";
float f1 = [str7 floatValue];
       
//6.NSString -> double
NSString * str8 = @"8.88";
double d1 = [str8 doubleValue];
       
//  :                     ,                
NSString * str9 = @“a123";
int i2 = [str9 intValue];
       
//7.             
 NSString * str10 = @“apple";
NSString * tmpStr1 = [str10 uppercaseString];
NSLog(@"tmpStr1 %@ str10 %@",tmpStr1,str10);
       
//8.            
NSString * str11 = @“APPLE";
NSString * tmpStr2 = [str11 lowercaseString];

//9.      
NSString * str12 = @“apple";
NSString * tmpStr3 = [str12 capitalizedString];

두 번 째:문자열 재 구성

//1.            
int year = 1990;
int month = 8;
int day = 08;
NSString * date = [NSString stringWithFormat:@"%d %d %d ",year,month,day];

NSString * address = @“  ";
NSString * dateAndAddrss = [NSString stringWithFormat:@"%@  :%@",date,address];

//2.            
NSString * str1 = @"apple.";
NSString * str2 = [str1 stringByAppendingString:@"iphone"];

//3.           
NSString * str3 = @"apple";
NSRange range = {4,0};
//location             ,length              
NSString * str4 = [str3 stringByReplacingCharactersInRange:range withString:@"iphone"];

//4.      ,       
NSString * str5 = @“apple,iPhone";
NSString * str6 = [str5 stringByReplacingOccurrencesOfString:@“p" withString:@“q"];

//5.                   hhs
NSString * str7 = @“apple-iphone—.iwatch.itouch";
NSString * str8 = [str7 stringByReplacingOccurrencesOfString:@"-" withString:@""];

//6.         
NSString * str9 = @“apple iPhone iwatch";
NSString * str10 = [str9 stringByReplacingOccurrencesOfString:@" " withString:@""];

세 번 째:문자열 쓰기 파일

  3.1:         
NSString * content = @"          ";
NSString * path = @"/Users/tengfei/Desktop/test.txt";
//1.NSString *:       (         )
//2.atomically : YES
//3.NSUTF8StringEncoding          
//4.NSError           
NSError * error;
//writeToFile:<#(NSString *)#> atomically:<#(BOOL)#> encoding:<#(NSStringEncoding)#> error:<#(NSError *__autoreleasing *)#>
BOOL result = [content writeToFile:path atomically:YES encoding:NSUTF8StringEncoding error:&error];

if(result)
{
    NSLog(@"      ");
}
else
{
    NSLog(@"error %@",error);
}

  3.2：           
  //       
  //        ,          ,              
NSString * path = @"/Users/tengfei/Desktop/test.txt";
NSError * error;
NSString * str = [NSString stringWithContentsOfFile:path encoding:NSUTF8StringEncoding error:&error];

if (error != nil)
{
    NSLog(@"error message %@",error);
}
else
{
    NSLog(@"str content %@",str);
}

넷 째:가 변 문자열

//1.       
//NSMutableString     NSString
//NSMutableString   NSString         
//NSMutableString * muStr = [[NSMutableString alloc] init];
NSMutableString * muStr = [[NSMutableString alloc] initWithCapacity:0];

//         
[muStr setString:@"apple"];

//             
[muStr appendString:@".com"];

//        ,     
[muStr insertString:@“iphone" atIndex:3];

//          
//       ,              ,    Range or index out of bounds
NSRange range = {3,7};
// [muStr deleteCharactersInRange:range];

[muStr replaceCharactersInRange:range withString:@"  "];