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Formatting Numbers – NSNumberFormatter Examples

// Get access to a file manager as our means
// to perform file operations
NSFileManager *fileManager = [NSFileManager defaultManager];
 
// Using the application home directory, get dictionary of attributes
NSDictionary *attributesDict = [fileManager attributesOfFileSystemForPath:NSHomeDirectory() error:NULL];
 
// Print total file system size and available space
NSLog(@"System size: %lld", [[attributesDict objectForKey:NSFileSystemSize] longLongValue]);
NSLog(@"System free space: %lld", [[attributesDict objectForKey:NSFileSystemFreeSize] longLongValue]);    
 
// Create formatter
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];  
 
//--------------------------------------------
// Set to decimal style and output to console
//--------------------------------------------
[formatter setNumberStyle:NSNumberFormatterDecimalStyle];
NSString *formattedOutput = [formatter stringFromNumber:[attributesDict objectForKey:NSFileSystemFreeSize]];
NSLog(@"System free space: %@", formattedOutput);

//--------------------------------------------
// Format style as currency, output to console
//--------------------------------------------
[formatter setNumberStyle:NSNumberFormatterCurrencyStyle];
formattedOutput = [formatter stringFromNumber:[attributesDict objectForKey:NSFileSystemFreeSize]];
NSLog(@"Output as currency: %@", formattedOutput);
 
//--------------------------------------------
// Change local and output as currency
//--------------------------------------------
NSLocale *locale = [[NSLocale alloc] initWithLocaleIdentifier:@"it_IT"];
[formatter setLocale:locale];
formattedOutput = [formatter stringFromNumber:[attributesDict objectForKey:NSFileSystemFreeSize]];
NSLog(@"Output as currency - locale it_IT: %@", formattedOutput);

//--------------------------------------------
// Format style as percentage, output to console
//--------------------------------------------
[formatter setNumberStyle:NSNumberFormatterPercentStyle];
 
// Set to the current locale
[formatter setLocale:[NSLocale currentLocale]];
 
// Get percentage of system space that is available
float percent = [[attributesDict objectForKey:NSFileSystemFreeSize] floatValue] / [[attributesDict objectForKey:NSFileSystemSize] floatValue];
NSNumber *num = [NSNumber numberWithFloat:percent];
formattedOutput = [formatter stringFromNumber:num];
NSLog(@"Percentage of system space available: %@", formattedOutput);

//--------------------------------------------
// Format style as "spell-out" output to console
//--------------------------------------------
[formatter setNumberStyle:NSNumberFormatterSpellOutStyle];
formattedOutput = [formatter stringFromNumber:[attributesDict objectForKey:NSFileSystemFreeSize]];
 
NSLog(@"Spell out: %@", formattedOutput);
 
// Clean up
[formatter release];
[locale release];

Comments

• Marin Todorov says:

  June 16, 2010 at 6:56 am

  As always excellent example, thank you :)

  In the last code blog I think I see a code creep :)
  #define debug(format, …) CFShow([NSString stringWithFormat:format, ## __VA_ARGS__]);

  Cheers, Marin

  [Reply]
• John Muchow says:

  June 16, 2010 at 7:34 am

  Thanks Marin, yes that was some debug code I prefer to use over NSLog…I’ve removed the code.

  [Reply]
• Lucas Longo says:

  June 16, 2010 at 5:14 pm

  Any way to convert seconds into hours:minutes:seconds easily?

  [Reply]

  

  John Muchow Reply:
  June 16th, 2010 at 6:42 pm

  There may be a way to use the NSDate class, however it may come down to doing the math yourself – divide by 3600 to get the hours, divide remainder by 60 to get minutes, etc. Anyone know of a better way ?

  [Reply]
• Patrick says:

  July 2, 2010 at 7:38 pm

  For fun, you can use NSNumberFormatter to make a calculator that provides output in the spell-out style.

  Throw together a quick window in IB, add 10 buttons for numbers, add four buttons for +, -, x, and divide, and one button for equals. Write some quick methods in Xcode, hook up the buttons to the methods. Oh yeah, create two outputs in IB, one for the numbers and one (larger) for the spell-out. Then have your equal method set the number output and spell-out output.

  Quick and fun.

  Also, you can add your (male hetronormative assumption ahead) wife’s name in the output randomly, or when the result is her age, or something. Throw the icon on the desktop and wait for her to need some calcs (or drag her over and force her to do some calcs).

  Great fun, then she can go back to her normal life.

  [Reply]
• AD says:

  July 4, 2010 at 2:10 pm

  Can you post an example where instead of putting £2,000,000 it displays £2m, or say £10.5m. It should work on smaller figures too: ie: 1k, 0.75k, 3.25k, etc.

  Thanks

  [Reply]
• BFleming says:

  October 4, 2010 at 4:32 pm

  I want the number 123456789.1234567 formatted to only 9 integers.

  But setting max integers truncates from right to left, so maxints set to 3 you get:

  789.2134567

  I want 123.1234567

  Is there a way to do this with just the formatter?

  [Reply]
• Bhaskar says:

  November 9, 2011 at 7:56 am

  Thanks for your code, its helps me more.
  But i have an issue,i used your code in ‘textfieldshouldEndEditing’, first time its work normally but when we going back to the textfield , and coming out of it , then the value changes.

  For example i entered value for first time is 123456789123456789
  and got this output 123,456,789,123,456,789
  and now when we re-enter and exit from the textfield with or without editing, i am getting the value is 123.

  and other issue is, its formatting upto 18 characters only
  If entered more than 18 we getting other answer i.e., 9,223,372,036,854,775,807.

  Thanks in advance
  Bhaskar

  [Reply]