¿Cómo comprobar si NSString es numérico o no

Question

Duplicar posible:
iphone how to check that a string is numeric only

tengo una NSString, entonces yo quiero comprobar la cadena es el número o no.

quiero decir

NSString *val = @"5555" ; 

if(val isNumber){ 
    return true; 
}else{ 
    retun false; 
} 

¿Cómo puedo hacer esto en C Objetivo?

Answer 1

Usted podría utilizar rangeOfCharacterFromSet::

@interface NSString (isNumber) 
-(BOOL)isInteger; 
@end 

@interface _IsNumber 
+(void)initialize; 
+(void)ensureInitialization; 
@end 

@implementation NSString (isNumber) 
static NSCharacterSet* nonDigits; 
-(BOOL)isInteger { 
    /* bit of a hack to ensure nonDigits is initialized. Could also 
     make nonDigits a _IsNumber class variable, rather than an 
     NSString class variable. 
    */ 
    [_IsNumber ensureInitialization]; 
    NSRange nond = [self rangeOfCharacterFromSet:nonDigits]; 
    if (NSNotFound == nond.location) { 
     return YES; 
    } else { 
     return NO; 
    } 
} 
@end 

@implementation _IsNumber 
+(void)initialize { 
    NSLog(@"_IsNumber +initialize\n"); 
    nonDigits = [[NSCharacterSet decimalDigitCharacterSet] invertedSet]; 
} 
+(void)ensureInitialization {} 
@end 

Answer 2

Uso [NSNumberFormatter numberFromString: s]. Devuelve nil si la cadena especificada no es numérica. Puede configurar NSNumberFormatter para definir "numérico" para su escenario particular.

#import <Foundation/Foundation.h> 

int 
main(int argc, char* argv[]) 
{ 
    NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init]; 
    NSLocale *l_en = [[NSLocale alloc] initWithLocaleIdentifier: @"en_US"]; 
    NSLocale *l_de = [[NSLocale alloc] initWithLocaleIdentifier: @"de_DE"]; 
    NSNumberFormatter *f = [[NSNumberFormatter alloc] init]; 
    [f setLocale: l_en]; 

    NSLog(@"returned: %@", [f numberFromString: @"1.234"]); 

    [f setAllowsFloats: NO]; 
    NSLog(@"returned: %@", [f numberFromString: @"1.234"]); 

    [f setAllowsFloats: YES]; 
    NSLog(@"returned: %@", [f numberFromString: @"1,234"]); 

    [f setLocale: l_de]; 
    NSLog(@"returned: %@", [f numberFromString: @"1,234"]); 

    [l_en release]; 
    [l_de release]; 
    [f release]; 
    [pool release]; 
}