Iterator Reference

Iterator is an abstract base class that all other iterator classes inherit from.

var iterator = [0, 1, 2].iter();

Methods

all

Returns true if all values match the predicate, otherwise false.

var is_even = [2, 4, 6].iter().all((value) -> value % 2 == 0); // true

Parameters

predicate: (dyn!) -> Boolean - The predicate that each value must be true for.

Returns

Boolean - true if every value matches the predicate, otherwise false.

any

Returns true if any of the values match the predicate, otherwise false.

var is_at_least_one_even = [1, 4, 6].iter().any((value) -> value % 2 == 0); // true

Parameters

predicate: (dyn!) -> Boolean - The predicate that each value could be true for.

Returns

Boolean - true if any value matches the predicate, otherwise false.

chain

Combines two iterators.

var iter = Range(0, 3).chain([3, 4].iter());

Parameters

other: Iterator - The other iterator to add.

Returns

ChainIterator - A ChainIterator combining the two iterators.

collect

Collects an iterator to an array.

var arr = Range(0, 3).collect(); // [0, 1, 2]

Parameters

None

Returns

[dyn!] - An array of each item in the iterator.

count

Counts the items in an iterator.

var count = Range(0, 3).count(); // 3

Parameters

None

Returns

Number - The number of items in the iterator.

enumerate

Enumerates the iterator, zipping it with incrementing numbers.

var iter = ["first", "second", "third"].iter().enumerate();

Parameters

start: Number? optional - The number to start enumerating with. Defaults to 0.

Returns

EnumerateIterator - An EnumerateIterator enumerating the iterator.

has_next

var iter = [“first”, “second”, “third”.iter().has_next(); // true

Parameters

None

Returns

Boolean - Returns true if the iterator has more items, otherwise false.

filter

Filters an iterator by a predicate.

var iter = ["first", "second", "third"].iter().filter((word) -> word.length() > 5);

Parameters

predicate: (dyn!) -> Boolean - The predicate to filter the iterator by.

Returns

FilterIterator - A FilterIterator for filtering the iterator.

filter_indexed

Filters an iterator by a predicate and provides an index.

var iter = ["first", "second", "third"].iter().filter_indexed((i, word) -> word.length() > 5 or i == 0);

Parameters

predicate: (Number, dyn!) -> Boolean - The transform function where the first parameter is the index, and the second parameter is the element of the array.

Returns

FilterIndexedIterator - A FilterIndexedIterator for filtering the iterator.

find

Finds an item in an iterator by a predicate.

var iter = ["first", "second", "third"].iter().find((word) -> word.length() == 6);

Parameters

predicate: (dyn!) -> Boolean - The predicate to filter the iterator by.

Returns

dyn? - The value if found, otherwise nil.

flat_map

Transforms each item of the iterator, returning a new iterator.

var iter = [0, 1, 2].iter().flat_map((value) -> Range(0, value));

Parameters

transform: (dyn!) -> Iterator - The transform function.

Returns

FlatMapIterator - A FlatMapIterator for wrapping items in an iterator with an iterator.

fold

Iterates over an iterator, updates an accumlator, then returns it.

var iter = [1, 2, 3].iter().fold(0, (acc, value) -> acc + value); // 6

Parameters

initial: dyn! - The initial accumulator value for the fold.

reduce_function: (dyn!, dyn!) -> dyn! - A function that takes in the current accumlator and current value, and returns the next accumulator.

Returns

dyn? - The final accumulated value.

for_each

Iterates over each element in the iterator.

Range(0, 3).for_each(println);
// 0
// 1
// 2

Parameters

consumer: (dyn!) -> nil - A function to call on each item in the iterator.

Returns

nil

for_each_indexed

Iterates over each element in the iterator.

Range(0, 3).for_each_indexed((i, value) -> {
  println("Number " + (i + 1) + ": " + to_string(value));
});
// "Number 1: 0"
// "Number 2: 1"
// "Number 3: 2"

Parameters

consumer: (Number, dyn!) -> nil - A function to call on each item in the iterator. The first paramter is the index of the item, and the second is the item in the iterator.

Returns

nil

map

Iterates over each element and transforms them.

Range(0, 3).map((value) -> value + 1);

Parameters

transform: (dyn!) -> dyn! - A function to call on each item in the iterator to transform it.

Returns

MapIterator - A MapIterator for transforming items in an iterator.

map_indexed

Iterates over each element and transforms them.

Range(0, 3).map_indexed((i, value) -> i + value);

Parameters

transform: (Number, dyn!) -> dyn! - A function to call on each item in the iterator to transform it. The first parameter is an index, and the second parameter is the item at that index.

Returns

MapIndexedIterator - A MapIndexedIterator for transforming items in an iterator.

next

var iter = [“first”, “second”, “third”].iter().next(); // “first”

Parameters

None

Returns

dyn! - The next item in the iterator.

reduce

Iterates over an iterator, updates an accumlator, then returns it.

var iter = [1, 2, 3].iter().reduce((acc, value) -> acc + value); // 6

Parameters

reduce_function: (dyn!, dyn!) -> dyn! - A function that takes in the current accumlator and current value, and returns the next accumulator. The first accumulator value is the first element of the iterator.

Returns

dyn? - The final accumulated value.

reverse

Collects and reverses the items in an iterator.

var iter = [1, 2, 3].iter().reduce((acc, value) -> acc + value); // 6

Parameters

None

Returns

ArrayIterator - The iterator with its items reversed.

skip

Skips a number of items in the iterator.

var iter = Range(0, 10).skip(5);

Parameters

limit: Number - How many items to skip.

Returns

An Iterator with first provided number of items skipped.

take

Takes a number of items from the beginning of the iterator.

var iter = Range(0, 10).take(5);

Parameters

limit: Number - How many items to take.

Returns

TakeIterator - A TakeIterator for taking the provided number of items.

zip

Zips two iterators together into an iterator of Pairs.

var iter = Range(0, 5).zip(Range(5, 10));

Parameters

other: Iterator - The other iterator to zip with.

Returns

ZipIterator - A ZipIterator for zipping two iterators together into an iterator of Pairs.

Example

var even_numbers = Range(0, 10).iter()
  .filter((value) -> value % 2 == 0)
  .map((value) -> to_string(value))
  .collect(); // ["0", "2", "4", "6", "8"]