`stringWithFormat:` for the sophisticated hacker set
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FormatterKit Example



FormatterKit is a collection of well-crafted NSFormatter subclasses for things like hours of operation, 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):

  • Arrays: Display NSArray elements in a comma-delimited list (eg. "Russell, Spinoza & Rawls")
  • Hours of Operation: Format and collapse recurring weekly business hours (eg. "Mon-Wed: 8:00AM - 7:00PM")
  • 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 (eg. "3 minutes ago" / "yesterday")
  • URL Requests: Print out cURL or Wget command equivalents for any NSURLRequest (eg. curl "https://api.gowalla.com/spots/" -H "Accept: application/json")


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


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] autorelease];
[arrayFormatter setUsesAbbreviatedConjunction:YES]; // Use '&' instead of 'and'
[arrayFormatter setUsesSerialDelimiter:NO]; // Omit Oxford Comma
NSLog(@"%@", [arrayFormatter stringFromArray:list]); // # => "Russell, Spinoza & Rawls"


Modeling and displaying hours of operation is tricky business. It's perhaps one of the most prolific ratholes that has ever existed--a trap that has ensnared many a venturing programmer with its tendrils of perceived simplicity and maddening edge-cases.

TTTHoursOfOperation makes it easy to programmatically do the following:

Mon-Wed: 8:00AM - 7:00PM
Thu: 9:00AM - 12:00PM, 3:00PM - 10:00PM
Fri: Closed
Weekends: 11:00AM - 1:00AM

Additional features include:

  • Built-in hours parser to handle simply-formatted input, such as "08:45-15:00,17:00-22:00" or "closed"
  • Check if the current time is within today's store hours, or get the NSDates associated with this weeks hours for a particular weekday
  • Wrap-around time support, i.e. "20:00-26:00" would be the hours 8PM - 2AM, associated with a specified weekday
  • Localized output, such that a Japanese user, for example would see hours in a format like "火: 8:00 - 20:00" or "閉店"

Example Usage

TTTWeeklyHoursOfOperation *hoursOfOperation = [[TTTWeeklyHoursOfOperation alloc] init];
[hoursOfOperation setHoursWithString:@"08:00-19:00" forWeekday:TTTMonday];
[hoursOfOperation setHoursWithString:@"08:00-19:00" forWeekday:TTTTuesday];
[hoursOfOperation setHoursWithString:@"08:00-19:00" forWeekday:TTTWednesday];
[hoursOfOperation setHoursWithString:@"09:00-12:00,15:00-22:00" forWeekday:TTTThursday];
[hoursOfOperation setHoursWithString:@"closed" forWeekday:TTTFriday];
[hoursOfOperation setHoursWithString:@"11:00-25:00" forWeekday:TTTSaturday];
[hoursOfOperation setHoursWithString:@"11:00-25:00" forWeekday:TTTSunday];


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

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)


Core Foundation's 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 venu à la 2eme 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]; // "yesterday"
[timeIntervalFormatter setUsesIdiomaticDeicticExpressions:NO];
[timeIntervalFormatter stringForTimeInterval:100000]; // "1 day ago"

// 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:3]; 
[timeIntervalFormatter stringForTimeInterval:3]; // "seconds ago"


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 GET http://api.gowalla.com/spots, 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:@"http://api.gowalla.com/spots"]] autorelease];
[request setHTTPMethod:@"POST"];
[request addValue:@"application/json" forHTTPHeaderField:@"Accept"];
[TTTURLRequestFormatter cURLCommandFromURLRequest:request];
curl -X POST "https://api.gowalla.com/spots/" -H "Accept: application/json"


Mattt Thompson


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