NSNumberFormatter leading 0's and decimals

Question

Is there any way to format an NSNumber with leading 0's and decimals? For example, I need to have the ability to write 4.5 as well as 000. Currently I have it where it will allow decimals, but not leading 0's.

NSNumberFormatter *f = [[NSNumberFormatter alloc] init];
f.numberStyle = NSNumberFormatterNoStyle;

NSString *myString = [f numberFromString:@"4.5"];
NSLog(@"myString: %@",myString);

NSString *myOtherString = [f numberFromString:@"000"];
NSLog(@"myOtherString:%@",myOtherString);

The output from above would be: 'myString:4.5' and 'myOtherString:0'. I need to be able to do both '4.5' and '000' as output.

I have looked at Apple's "Data Formatting Guide" without much success.

Answer 1

Note that [f numberFromString:@"4.5"] returns an NSNumber* not a NSString*

You want something like this:

NSNumberFormatter *f = [[NSNumberFormatter alloc] init];
f.numberStyle = NSNumberFormatterNoStyle;

NSNumber *myNumber;
NSString *myString;

myNumber = [f numberFromString:@"4.5"];
[f setNumberStyle:kCFNumberFormatterDecimalStyle];
myString = [f stringFromNumber:myNumber];
NSLog(@"myString: %@",myString);

myNumber = [f numberFromString:@"000"]; // Note that the extra zeros are useless
[f setFormatWidth:3];
[f setPaddingCharacter:@"0"];
myString = [f stringFromNumber:myNumber];
NSLog(@"myString: %@",myString);

NSLog output:

myString: 4.5
myString: 000

If you don't have strings to start with just create number like:

myNumber = [NSNumber numberWithFloat:4.5];
myNumber = [NSNumber numberWithInt:0];

Or just use standard formatting:

myString = [NSString stringWithFormat:@"%.1f", [myNumber floatValue]];
myString = [NSString stringWithFormat:@"%03d", [myNumber intValue]];

Or if you don't need an NSNumber representation just use standard formatting :

myString = [NSString stringWithFormat:@"%.1f", 4.5];
myString = [NSString stringWithFormat:@"%03d", 0];

Answer 2

You could try something like:

NSString *myString = [NSString stringWithFormat:@"%03f", [myNSNumber floatValue]];

This, following the printf format, will print your number forcing at least 3 digits to be printed and padding with '0's any empty space.

Answer 3

How about this as a variation on theme for the 000's

 NSNumber *myNumber;
NSString *myString =@"000" ;
NSString * myStringResult;
NSNumberFormatter *f = [[NSNumberFormatter alloc] init];
f.numberStyle = NSNumberFormatterNoStyle;
[f setHasThousandSeparators:FALSE]; //-- remove seperator
[f  setMinimumIntegerDigits:[myString length ]]; //-- set minimum number of digits to display using the string length.



myNumber = [f numberFromString:myString];



myStringResult = [f stringFromNumber:myNumber];
NSLog(@"myStringResult: %@",myStringResult);