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FormatterKit is a collection of well-crafted NSFormatter subclasses for things like units of information, distance, and relative time intervals. Each formatter abstracts away the complex business logic of their respective domain, so that you can focus on the more important aspects of your application.

In short, use this library if you're manually formatting any of the following (with string interpolation or the like):

  • Addresses: Create formatted address strings from components (e.g. 221b Baker St / Paddington / Greater London / NW1 6XE / United Kingdom )
  • Arrays: Display NSArray elements in a comma-delimited list (e.g. "Russell, Spinoza & Rawls")
  • Colors: RGB, CMYK, and HSL your ROY G. BIV in style. (e.g. #BADF00D, rgb(255, 100, 42))
  • Location, Distance & Direction: Show CLLocationDistance, CLLocationDirection, and CLLocationSpeed in metric or imperial units (eg. "240ft Northwest" / "45 km/h SE")
  • Ordinal Numbers: Convert cardinal NSNumber objects to their ordinal in most major languages (eg. "1st, 2nd, 3rd" / "1ère, 2ème, 3ème")
  • Time Intervals: Show relative time distance between any two NSDate objects (e.g. "3 minutes ago" / "yesterday")
  • Units of Information: Humanized representations of quantities of bits and bytes (e.g. "2.7 MB")
  • URL Requests: Print out cURL or Wget command equivalents for any NSURLRequest (e.g. curl -X POST "" -H "Accept: text/html")

FormatterKit, along with TransformerKit & InflectorKit provide well-designed APIs for manipulating user-facing content.


FormatterKit comes fully internationalized, with .strings files for the following locales:

  • Catalan (ca)
  • Chinese (Simplified) (zh_Hans)
  • Chinese (Traditional) (zh_Hant)
  • Czech (cs)
  • Danish (da)
  • Dutch (nl)
  • English (en)
  • German (de)
  • Greek (el)
  • French (fr)
  • Indonesian (id)
  • Italian (it)
  • Korean (ko)
  • Norwegian Bokmål (nb)
  • Norwegian Nynorsk (nn)
  • Polish (pl)
  • Portuguese (Brazilian) (pt_BR)
  • Russian (ru)
  • Spanish (es)
  • Swedish (sv)
  • Turkish (tr)
  • Ukranian (uk)
  • Vietnamese (vi)

If you'd like to contribute an additional localization, feel free to open a new pull request.

Removing Unused Localizations

Because the App Store automatically attempts to determine supported locales, and FormatterKit includes localizations for the aforementioned locales, you may want to remove the .strings file and .lproj directory. You can do this most easily by having the following command run in a new Build Phase:

    $ find "$TARGET_BUILD_DIR" -maxdepth 8 -type f -name "FormatterKit.strings" -execdir rm -r -v {} \;

If you are using CocoaPods, you may want to remove unwanted localizations using the pre install script below. Modify the supported_locales array to match your supported locales and paste it into your Podfile.

pre_install do |installer|
    supported_locales = ['da', 'en']

    installer.pods.each do |pod|
        %x[ find "#{pod.root}" -name '*.lproj' ].split.each do |bundle|
            if (!supported_locales.include?(File.basename(bundle, ".lproj").downcase))
                puts "Removing #{bundle}"


Build and run the FormatterKit Example project in Xcode to see an inventory of the available FormatterKit components.


Address formats vary greatly across different regions. TTTAddressFormatter ties into the Address Book frameworks to help your users find their place in the world.

For example, addresses in the United States take the form:

Street Address
City State ZIP

Whereas addresses in Japan follow a different convention:

Postal Code
Prefecture Municipality
Street Address

Requires the AddressBook and AddressBookUI frameworks are included, with #import statements in Prefix.pch. Only available on iOS.

Example Usage

TTTAddressFormatter *addressFormatter = [[TTTAddressFormatter alloc] init];
NSLog(@"%@", [addressFormatter stringFromAddressWithStreet:street locality:locality region:region postalCode:postalCode country:country]);


Think of this as a production-ready alternative to NSArray -componentsJoinedByString:. TTTArrayFormatter comes with internationalization baked-in, and provides a concise API that allows you to configure for any edge cases.

Example Usage

NSArray *list = [NSArray arrayWithObjects:@"Russel", @"Spinoza", @"Rawls", nil];
TTTArrayFormatter *arrayFormatter = [[TTTArrayFormatter alloc] init];
[arrayFormatter setUsesAbbreviatedConjunction:YES]; // Use '&' instead of 'and'
[arrayFormatter setUsesSerialDelimiter:NO]; // Omit Oxford Comma
NSLog(@"%@", [arrayFormatter stringFromArray:list]); // # => "Russell, Spinoza & Rawls"


RGB, CMYK, and HSL your ROY G. BIV in style. TTTColorFormatter provides string representations of colors.

Example Usage

TTTColorFormatter *colorFormatter = [[TTTColorFormatter alloc] init];
NSString *RGB = [colorFormatter RGBStringFromColor:[UIColor orangeColor]];


When working with CoreLocation, you can use your favorite unit for distance... so long as your favorite unit is the meter. If you want to take distance calculations and display them to the user, you may want to use kilometers instead, or maybe even miles, if you're of the Imperial persuasion.

TTTLocationFormatter gives you a lot of flexibility in the display of coordinates, distances, direction, speed, and velocity. Choose Metric or Imperial, cardinal directions, abbreviations, or degrees, and configure everything else (number of significant digits, etc.), with the associated NSNumberFormatter.

Example Usage

TTTLocationFormatter *locationFormatter = [[TTTLocationFormatter alloc] init];
CLLocation *austin = [[CLLocation alloc] initWithLatitude:30.2669444 longitude:-97.7427778];
CLLocation *pittsburgh = [[CLLocation alloc] initWithLatitude:40.4405556 longitude:-79.9961111];

Distance in Metric Units with Cardinal Directions

NSLog(@"%@", [locationFormatter stringFromDistanceAndBearingFromLocation:pittsburgh toLocation:austin]);
// "2,000 km Southwest"

Distance in Imperial Units with Cardinal Direction Abbreviations

[locationFormatter.numberFormatter setMaximumSignificantDigits:4];
[locationFormatter setBearingStyle:TTTBearingAbbreviationWordStyle];
[locationFormatter setUnitSystem:TTTImperialSystem];
NSLog(@"%@", [locationFormatter stringFromDistanceAndBearingFromLocation:pittsburgh toLocation:austin]);
// "1,218 miles SW"

Speed in Imperial Units with Bearing in Degrees

[locationFormatter setBearingStyle:TTTBearingNumericStyle];
NSLog(@"%@ at %@", [locationFormatter stringFromSpeed:25],[locationFormatter stringFromBearingFromLocation:pittsburgh toLocation:austin]);
// "25 mph at 310°"


[locationFormatter.numberFormatter setUsesSignificantDigits:NO];
NSLog(@"%@", [locationFormatter stringFromLocation:austin]);
// (30.2669444, -97.7427778)


NSNumberFormatter is great for Cardinal numbers (17, 42, 69, etc.), but it doesn't have built-in support for Ordinal numbers (1st, 2nd, 3rd, etc.)

A naïve implementation might be as simple as throwing the one's place in a switch statement and appending "-st", "-nd", etc. But what if you want to support French, which appends "-er", "-ère", and "-eme" in various contexts? How about Spanish? Japanese?

TTTOrdinalNumberFormatter supports English, Spanish, French, German, Irish, Italian, Japanese, Dutch, Portuguese, and Mandarin Chinese. For other languages, you can use the standard default, or override it with your own. For languages whose ordinal indicator depends upon the grammatical properties of the predicate, TTTOrdinalNumberFormatter can format according to a specified gender and/or plurality.

Example Usage

TTTOrdinalNumberFormatter *ordinalNumberFormatter = [[TTTOrdinalNumberFormatter alloc] init];
[ordinalNumberFormatter setLocale:[NSLocale currentLocale]];
[ordinalNumberFormatter setGrammaticalGender:TTTOrdinalNumberFormatterMaleGender];
NSNumber *number = [NSNumber numberWithInteger:2];
NSLog(@"%@", [NSString stringWithFormat:NSLocalizedString(@"You came in %@ place!", nil), [ordinalNumberFormatter stringFromNumber:number]]);

Assuming you've provided localized strings for "You came in %@ place!", the output would be:

  • English: "You came in 2nd place!"
  • French: "Vous êtes arrivé à la 2e place !"
  • Spanish: "Usted llegó en 2.o lugar!"


Nearly every application works with time in some way or another, and most often when we display temporal information to users, it's in relative terms to the present. So "3 minutes ago", "10 months ago", or "last month".

iOS 4 introduced a -doesRelativeDateFormatting property for NSDateFormatter, but it falls back on an absolute time representation if no idiomatic expression is found. Instead, TTTTimeIntervalFormatter defaults to a smart relative display of an NSTimeInterval value, with options to extend that behavior to your particular use case.

Example Usage

TTTTimeIntervalFormatter *timeIntervalFormatter = [[TTTTimeIntervalFormatter alloc] init];
[timeIntervalFormatter stringForTimeInterval:0]; // "just now"
[timeIntervalFormatter stringForTimeInterval:-100]; // "1 minute ago"
[timeIntervalFormatter stringForTimeInterval:-8000]; // "2 hours ago"

// Turn idiomatic deictic expressions on / off
[timeIntervalFormatter stringForTimeInterval:-100000]; // "1 day ago"
[timeIntervalFormatter setUsesIdiomaticDeicticExpressions:YES];
[timeIntervalFormatter stringForTimeInterval:-100000]; // "yesterday"

// Customize the present tense deictic expression for
[timeIntervalFormatter setPresentDeicticExpression:@"seconds ago"];
[timeIntervalFormatter stringForTimeInterval:0]; // "seconds ago"

// Expand the time interval for present tense
[timeIntervalFormatter stringForTimeInterval:-3]; // "3 seconds ago"
[timeIntervalFormatter setPresentTimeIntervalMargin:10];
[timeIntervalFormatter stringForTimeInterval:-3]; // "seconds ago"


No matter how far abstracted from its underlying hardware an application may be, there comes a day when it has to communicate the size of a file to the user.

TTTUnitOfInformationFormatter transforms a number of bits or bytes and into a humanized representation, using either SI decimal or IEC binary unit prefixes.

Example Usage

TTTUnitOfInformationFormatter *unitOfInformationFormatter = [[TTTUnitOfInformationFormatter alloc] init];
[unitOfInformationFormatter stringFromNumberOfBits:[NSNumber numberWithInteger:416]]; // "56 bytes"

// Display in either bits or bytes
[unitOfInformationFormatter setDisplaysInTermsOfBytes:NO];
[unitOfInformationFormatter stringFromNumberOfBits:[NSNumber numberWithInteger:416]]; // "416 bits"

// Use IEC Binary prefixes (base 2 rather than SI base 10; see
[unitOfInformationFormatter setUsesIECBinaryPrefixesForCalculation:NO];
[unitOfInformationFormatter stringFromNumberOfBits:[NSNumber numberWithInteger:8660]]; // "8.66 Kbit"

[unitOfInformationFormatter setUsesIECBinaryPrefixesForCalculation:YES];
[unitOfInformationFormatter setUsesIECBinaryPrefixesForDisplay:YES];
[unitOfInformationFormatter stringFromNumberOfBits:[NSNumber numberWithInteger:416]]; // "8.46 Kibit"


NSURLRequest objects encapsulate all of the information made in a network request, including url, headers, body, etc. This isn't something you'd normally want to show to a user, but it'd be nice to have a way to make it more portable for debugging.

Enter TTTURLRequestFormatter. In addition to formatting requests simply as POST, it will also generate cURL and Wget commands with all of its headers and data fields intact to debug in the console.

Example Usage

NSMutableURLRequest *request = [[NSMutableURLRequest alloc] initWithURL:[NSURL URLWithString:@""]];
[request setHTTPMethod:@"POST"];
[request addValue:@"text/html" forHTTPHeaderField:@"Accept"];
[TTTURLRequestFormatter cURLCommandFromURLRequest:request];
curl -X POST "" -H "Accept: text/html"


Mattt Thompson


FormatterKit is available under the MIT license. See the LICENSE file for more info.

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