NSNumber storing float. Please NO scientific notation?

Question

My code looks like this

NSNumber *inputToNumber = [NSNumber numberWithFloat:[textField.text floatValue]];

the value from the textfield is actually a telephone number. It's stored in NSNumber as an annoying (2.0)78966e+08

How can I just get NSNumber to store it as 0207896608?

Answer 1

Scientific notation is used in may computer languages as the default output of very large (or very small) numbers. If you want the number to be output as a decimal, you need to specify the output format (the implementation varies by language.)

Also, julesjacobs is correct. You should not use FLOAT for a phone number as it is subject to binary rounding errors. Using INT or STRING will save you lots of headaches.

Answer 2

I think that the basic idea to store a phone number into a NSNumber is flawed:

• how do you discriminate between numbers with or without leading 0 ?
• how do you store phone numbers from foreign countries ?

I would use NSString in place of NSNumber.

Answer 3

Just because it's called a number doesn't mean a "telephone number" is a number in the same sense that "5" or "pi" are.

Either you should treat a telephone number as a string, or you should create a TelephoneNumber model class to represent each one.

Answer 4

Consider that there are places in the world where numbers don't have leading 0's and where a number with a leading 0 is not the same as the same number without a leading 0.

05843924 != 5843924

So stop being lazy with that NSNumber hacks and build your own phone-number class.

Answer 5

If you need to be able to deal with it as numbers maybe you should break it up into its parts, and store each part as an integer.

01112223333
country code 0
area code 111
prefix 222
number 3333

Or you could store the whole thing as a string if you don't need to manipulate it.

Answer 6

Are you storing a phone number in a float? You should consider using an integer or string. Perhaps:

NSNumber *inputToNumber = [NSNumber numberWithInt:[textField.text intValue]];

Answer 7

Hey Guys what do you think of this, It seems to full-fill my purposes. Only UK at the moment so will worry about localization when I get a chance.

I use this to get to store the number

NSNumber *inputToNumber = [NSNumber numberWithLongLong:(long long)[[textField.text stringByReplacingOccurrencesOfString:@" " withString:@""] longLongValue]];

And this method formats my telephone number and takes care of the preceeding 0 mentioned.

-(NSString *)phoneNumberString:(NSNumber *)phoneNumber {
    //Add a zero because NSNumber won't save a preceeding zero
    NSString *telephoneString = [[NSString alloc] initWithFormat:@"0%@", [phoneNumber stringValue]];

    if (telephoneString.length >= 4) {
        NSString *firstPart = [[NSString alloc] initWithString: [telephoneString substringToIndex:4]];
        NSString *secondPart = [[NSString alloc] initWithString: [telephoneString substringFromIndex:4]];

        //Add the two parts together with a space inbetween
        NSString *formattedTelephoneString = [NSString stringWithFormat:@"%@ %@", firstPart, secondPart];

        //send it back to the cellForRow TableCell Method
        [firstPart release];
        [secondPart release];
        [telephoneString release];

        return formattedTelephoneString;    
    }
    else {
        return telephoneString; 
    }
}

Thanks for all the comments. I'm gonna mark the answer as whoever suggested NSString as I fear I will revert to using NSString for this instead of my above workaround.