Discussion

Loops through an array to find whether all objects match the block.

Discussion

Loops through an array to find whether any object matches the block.

This method is similar to the Scala list exists. It is functionally identical to bk_match: but returns a BOOL instead. It is not recommended to use bk_any: as a check condition before executing bk_match:, since it would require two loops through the array.

For example, you can find if a string in an array starts with a certain letter:

 NSString *letter = @"A";
 BOOL containsLetter = [stringArray bk_any:^(id obj) {
   return [obj hasPrefix:@"A"];
 }];

Discussion

Enumerates through an array concurrently and executes the given block once for each object.

Enumeration will occur on appropriate background queues. This will have a noticeable speed increase, especially on dual-core devices, but you must be aware of the thread safety of the objects you message from within the block. Be aware that the order of objects is not necessarily the order each block will be called in.

Discussion

Tests whether every element of this array relates to the corresponding element of another array according to match by block.

For example, finding if a list of numbers corresponds to their sequenced string values; NSArray numbers = @[ @(1), @(2), @(3) ]; NSArray letters = @[ @“1”, @“2”, @“3” ]; BOOL doesCorrespond = [numbers bk_corresponds:letters withBlock:^(id number, id letter) { return [[number stringValue] isEqualToString:letter]; }];

Discussion

Loops through an array and executes the given block with each object.

Discussion

Call the block once for each object and create an array of the return values.

This is sometimes referred to as a transform, mutating one of each object: NSArray *new = [stringArray bk_map:^id(id obj) { return [obj stringByAppendingString:@“.png”]); }];

Discussion

Loops through an array to find the object matching the block.

bk_match: is functionally identical to bk_select:, but will stop and return on the first match.

Discussion

Loops through an array to find whether no objects match the block.

This selector performs literally the exact same function as bk_all: but in reverse.

Discussion

Arbitrarily accumulate objects using a block.

The concept of this selector is difficult to illustrate in words. The sum can be any NSObject, including (but not limited to) a string, number, or value.

For example, you can concentate the strings in an array: NSString *concentrated = [stringArray bk_reduce:@“” withBlock:^id(id sum, id obj) { return [sum stringByAppendingString:obj]; }];

You can also do something like summing the lengths of strings in an array: NSUInteger value = [[[stringArray bk_reduce:nil withBlock:^id(id sum, id obj) { return @([sum integerValue] + obj.length); }]] unsignedIntegerValue];

Discussion

Sometimes we just want to loop an objects list and reduce one property, where each result is a primitive type.

For instance, say we want to caculate the total balance from a list of people.

Code without using a block will be something like:

 NSArray *peoples = @[p1, p2, p3];
 CGFloat totalBalance = 0;
 for (People *people in peoples) {
     totalBalance += [people balance];
 }

We can use a block to make it simpler:

 NSArray *peoples = @[p1, p2, p3];
 CGFloat totalBalance = [peoples reduceFloat:.0f WithBlock:^CGFloat(CGFloat result, id obj, NSInteger index) {
     return result + [obj balance];
 }];

Discussion

Sometimes we just want to loop an objects list and reduce one property, where each result is a primitive type.

For example, say we want to calculate the total age of a list of people.

Code without using block will be something like:

 NSArray *peoples = @[p1, p2, p3];
 NSInteger totalAge = 0;
 for (People *people in peoples) {
     totalAge += [people age];
 }

We can use a block to make it simpler:

 NSArray *peoples = @[p1, p2, p3];
 NSInteger totalAge = [peoples reduceInteger:0 withBlock:^(NSInteger result, id obj, NSInteger index) {
     return result + [obj age];
 }];

Discussion

Loops through an array to find the objects not matching the block.

This selector performs literally the exact same function as bk_select: but in reverse.

This is useful, as one may expect, for removing objects from an array. NSArray *new = [computers bk_reject:^BOOL(id obj) { return ([obj isUgly]); }];

Discussion

Loops through an array to find the objects matching the block.