How to obtain an unformatted string representation of an NSDecimal or NSDecimalNumber?

问题

I have an NSDecimal and need this as technical string, i.e. with no formatting in any way. Floating point should be a "." if there is any, and minus sign should just be a "-" if there is any. besides that, there should be no formatting going on like grouping or chinese numbers.

I was looking for 2 hours through the SDK but it seems there is nothing simple to accomplish this. Are there solutions for this?

回答1:

For NSDecimal, you can use NSDecimalString with a specified locale:

NSLocale *usLocale = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US"];
NSString *decimalString =  NSDecimalString(&decimalValue, usLocale);
[usLocale release];

The U.S. locale uses a period for the decimal separator, and no thousands separator, so I believe that will get you the kind of formatting you're looking for.

As others have pointed out, for an NSDecimalNumber you can use the -descriptionWithLocale: method with the above-specified U.S. locale. This doesn't lose you any precision.

回答2:

NSDecimalNumber

NSLog(@"%@", [theNumber stringValue]);

NSDecimal

NSLog(@"%@", NSDecimalString(&theDecimal, nil));

回答3:

NSDecimalNumber is a subclass of NSNumber which has the -stringValue method.

stringValue

Returns the receiver’s value as a human-readable string.

- (NSString *)stringValue

Return Value

The receiver’s value as a human-readable string, created by invoking descriptionWithLocale: where locale is nil.

descriptionWithLocale:

Returns a string that represents the contents of the receiver for a given locale.

- (NSString *)descriptionWithLocale:(id)aLocale

Parameters aLocale

An object containing locale information with which to format the description. Use nil if you don’t want the description formatted.

Just call [theNumber stringValue].

回答4:

Use decimalNumberWithString from the NSDecimalNumber class:

NSDecimalNumber *dn = [NSDecimalNumber decimalNumberWithMantissa:12345
                                                        exponent:-100
                                                      isNegative:YES];
NSDictionary *local = nil;
NSString *ds = [dn descriptionWithLocale: local];
NSLog(@"dn: %@", dn);
NSLog(@"ds: %@", ds);

dn: -0.00000000000000000000000 … 0000000000000000000000000000000000012345
ds: -0.00000000000000000000000 … 0000000000000000000000000000000000012345

来源：https://stackoverflow.com/questions/1815664/how-to-obtain-an-unformatted-string-representation-of-an-nsdecimal-or-nsdecimaln