Ruby inspired categories to make Objective-C a little bit nicer to use.

Usage

Lanaguage Constructs

unless()

Equivalent to if (!conditional), it runs the unless code if the conditional is false and the else if it's true.

unless (1 != 1) {
    NSLog(@"This will be run because the conditional resolves to NO")
} else {
    NSLog(@"This would be run if the conditional resolved to YES")
}

NSArray

map:

Returns an array made of the return value of each call to the block.

NSArray *words = @[@"funny", @"little", @"frog"];

NSArray *mappedArray = [words map:id^(id item) {
    NSString *word = (NSString *)item;

    return @"yes";
}];

mappedArray == @[@"yes", @"yes", @"yes"]

join and join:

Creates a string by joining the elements of an array with either whitespace or a separator.

NSArray *words = @[@"funny", @"little", @"frog"];

[words join]; == @"funny little frog"
[words join:@"-"]; == @"funnny-little-frog"

isEmpty

Returns true if the array has no elements and false if it has any.

NSArray *words = @[@"funny", @"little", @"frog"];
[words isEmpty]; == NO

NSArray *noWords = @[]; 
[noWords isEmpty]; == YES

any:

Returns true if the array contains and elements passing the test in the block. Returns false if none pass the test.

NSArray *words = @[@"funny", @"little", @"frog"];

[words any:BOOL^(id item) {
    NSString *word = (NSString *)item;

    return [word isEqualToString:@"funny"];
}]; == YES

[words any:BOOL^(id item) {
    NSString *word = (NSString *)item;

    return [word isEqualToString:@"belle"];
}]; == NO

select:

Returns an array of the elements from an array that pass the test in the block.

NSArray *words = @[@"funny", @"little", @"frog"];

NSArray *selectedWords = [words select:^BOOL(id item) {
    NSString *word = (NSString *)item;

    return [word isEqualToString:@"funny"];
}]; == @[@"funny"]

selectedWords = [words select:^BOOL(id item) {
    NSString *word = (NSString *)item;

    return [word isEqualToString:@"belle"];
}]; == @[]

reject:

Returns an array of any elements that fail the test in the blok.

NSArray *words = @[@"funny", @"little", @"frog"];

NSArray *selectedWords = [words reject:^BOOL(id item) {
    NSString *word = (NSString *)item;

    return [word isEqualToString:@"funny"];
}]; == @[@"little", @"frog"]

selectedWords = [words reject:^BOOL(id item) {
    NSString *word = (NSString *)item;

    return [word isEqualToString:@"belle"];
}]; == @[@"funny", @"little", @"frog"]

each:

Executes a block for each element in an array.

NSArray *words = @[@"funny", @"little", @"frog"];

[words each:^(id item) {
    NSLog(@"This will be called once for each item in words");
}];

each_with_index:

Executes a block for each element in an array and passed in the index of the element.

NSArray *words = @[@"funny", @"little", @"frog"];

[words eachWithIndex:^(id item, int index) {
    NSLog(@"This will be called once for each item in words and pass the index of the item");
}];

NSNumber

times:

Executes the block however many times the number is equal to.

[@(4) times:{
    NSLog(@"This block will be called 4 times.")
}];

timesWithIndex:

Executes the block however many times the number is equal to. Passes in the index of the current iteration.

[@(4) times:^(int i) {
    NSLog(@"This block will be called 4 times and will pass the count each time")
}];

toString

Converts an NSNumber to an NSString.

[@(42) toString]; == 42

NSString

join: and join:with:

Creates a new string by concatenating two strings with either a space or the specified separator.

[[@"funny" join:@"little"] join:@"frog"]; == @"funny little frog"

[[@"funny" join:@"little" with:@"-"] join:@"frog" with:@"-"]; == @"funny-little-frog"

isEmpty

Returns true if the length of the string is 0 and false if it's greater than 0.

NSString *text = @"";   
[text isEmpty]; == YES

NSString *text = @"funny little frog";
[text isEmpty]; == NO

chomp and chomp:

Removes the specified string from the end of a string or removes \n if no string is specified.

NSString *text = @"funny little frog\n";
[text chomp]; == @"funny little frog"   
[text chomp:@"frog"]; == @"funny little "

toNum

Converts an NSString to an NSNumber.

[@"42" toNum]; == @(42)

gsub:with:

Replaces a matched string with the specified string.

[@"Adam" gsub:@"Adam" with:@"Help"]; == "Help"

split and split:

Returns an array that divides the string by whitespace or the specified separator.

[@"funny little frog" split]; == @[@"funny", @"little", @"frog"]
[@"funny-little frog" split:@"-"]; == @[@"funny", @"little frog"]

index:

Returns the index of the first occurrence of a string in another string.

[@"funny little frog" index:@"little"]; == 6
[@"funny little frog" index:@"belle"]; == -1