Iterators

Iterators can be used in for-in loops. All iterators must have two methods

hasNext: This should return a Bool indicating whether there are any more items left

next: This should return the next element in the sequence

Iterators that extend the class Iterator get the following methods

  • each(fn)

    Calls function fn for all items in the iterator

    Example:

    let a=[]
[1,2,3].iter().each(|x|a.push(x))
a //[1,2,3]

  • all(fn)

    Returns if for all items in the interator fn(item) is truthy

    Example: [1,2,3].iter().all(|x|x<10) //true

  • any(fn)

    Returns if for any item in the iterator fn(item) is truthy

    Example: [1,2,3].iter().any(|x|x==1) //true

  • map(fn)

    Returns a new iterator whose items are fn(item) of the items of this iterator

    Example: [1,2,3].map(|x|x+1).collect() //[2,3,4]

  • filter(fn)

    Returns a new iterator whose items are those items of this iterator for which fn(item) is truthy

    Example: [1,2,3].filter(|x|x%2==1).collect() //[1,3]

  • collect()

    Collects all items of the iterator into an array

    Example: [1,2,3].iter().collect() //[1,2,3]

  • count()

    Returns the number of items of the iterator

    Example: [1,2,3].iter().count() //3

  • reduce(fn,initial)

    Applys fn, a function of two arguments cummulatively to the items of the iterator starting with initial

    Example: [1,2,3].iter().reduce(|x,y|x+y,0) //6