path: root/api/lists.yaml

List.binary_search:
  description: >
    Performs a binary search on a sorted list.
  return:
    type: 'Int'
    description: >
      Assuming the input list is sorted according to the given comparison function,
      return the index where the given item would be inserted to maintain the sorted
      order. That is, if the item is found, return its index, otherwise return the
      place where it would be found if it were inserted and the list were sorted.
  args:
    list:
      type: '[T]'
      description: >
        The sorted list to search.
    by:
      type: 'func(x,y:&T->Int32)'
      default: 'T.compare'
      description: >
        The comparison function used to determine order. If not specified, the
        default comparison function for the item type will be used.
  example: |
    >> [1, 3, 5, 7, 9].binary_search(5)
    = 3
    
    >> [1, 3, 5, 7, 9].binary_search(-999)
    = 1
    
    >> [1, 3, 5, 7, 9].binary_search(999)
    = 6
    
List.by:
  description: >
    Creates a new list with elements spaced by the specified step value.
  return:
    type: '[T]'
    description: >
      A new list with every `step`-th element from the original list.
  args:
    list:
      type: '[T]'
      description: >
        The original list.
    step:
      type: 'Int'
      description: >
        The step value for selecting elements.
  example: |
    >> [1, 2, 3, 4, 5, 6].by(2)
    = [1, 3, 5]
    
List.clear:
  description: >
    Clears all elements from the list.
  return:
    type: 'Void'
    description: >
      Nothing.
  args:
    list:
      type: '@[T]'
      description: >
        The mutable reference to the list to be cleared.
  example: |
    >> my_list.clear()
    
List.counts:
  description: >
    Counts the occurrences of each element in the list.
  return:
    type: '{T=Int}'
    description: >
      A table mapping each element to its count.
  args:
    list:
      type: '[T]'
      description: >
        The list to count elements in.
  example: |
    >> [10, 20, 30, 30, 30].counts()
    = {10=1, 20=1, 30=3}
    
List.find:
  description: >
    Finds the index of the first occurrence of an element (if any).
  return:
    type: 'Int?'
    description: >
      The index of the first occurrence or `!Int` if not found.
  args:
    list:
      type: '[T]'
      description: >
        The list to search through.
    target:
      type: 'T'
      description: >
        The item to search for.
  example: |
    >> [10, 20, 30, 40, 50].find(20)
    = 2 : Int?
    
    >> [10, 20, 30, 40, 50].find(9999)
    = none : Int?
    
List.first:
  description: >
    Find the index of the first item that matches a predicate function (if any).
  return:
    type: 'Int'
    description: >
      Returns the index of the first item where the predicate is true or `!Int` if no
      item matches.
  args:
    list:
      type: '[T]'
      description: >
        The list to search through.
    predicate:
      type: 'func(item:&T -> Bool)'
      description: >
        A function that returns `yes` if the item should be returned or
        `no` if it should not.
  example: |
    >> [4, 5, 6].find(func(i:&Int): i.is_prime())
    = 5 : Int?
    >> [4, 6, 8].find(func(i:&Int): i.is_prime())
    = none : Int?
    
List.from:
  description: >
    Returns a slice of the list starting from a specified index.
  return:
    type: '[T]'
    description: >
      A new list starting from the specified index.
  args:
    list:
      type: '[T]'
      description: >
        The original list.
    first:
      type: 'Int'
      description: >
        The index to start from.
  example: |
    >> [10, 20, 30, 40, 50].from(3)
    = [30, 40, 50]
    
List.has:
  description: >
    Checks if the list has an element.
  return:
    type: 'Bool'
    description: >
      `yes` if the list has the element, `no` otherwise.
  args:
    list:
      type: '[T]'
      description: >
        The list to check.
    target:
      type: 'T'
      description: >
        The element to check for.
  example: |
    >> [10, 20, 30].has(20)
    = yes
    
List.heap_pop:
  description: >
    Removes and returns the top element of a heap or `none` if the list is empty.
    By default, this is the *minimum* value in the heap.
  return:
    type: 'T?'
    description: >
      The removed top element of the heap or `none` if the list is empty.
  args:
    list:
      type: '@[T]'
      description: >
        The mutable reference to the heap.
    by:
      type: 'func(x,y:&T->Int32)'
      default: 'T.compare'
      description: >
        The comparison function used to determine order. If not specified, the
        default comparison function for the item type will be used.
  example: |
    >> my_heap := [30, 10, 20]
    >> my_heap.heapify()
    >> my_heap.heap_pop()
    = 10
    
List.heap_push:
  description: >
    Adds an element to the heap and maintains the heap property. By default, this
    is a *minimum* heap.
  return:
    type: 'Void'
    description: >
      Nothing.
  args:
    list:
      type: '@[T]'
      description: >
        The mutable reference to the heap.
    item:
      type: 'T'
      description: >
        The item to be added.
    by:
      default: 'T.compare'
      description: >
        The comparison function used to determine order. If not specified, the
        default comparison function for the item type will be used.
  example: |
    >> my_heap.heap_push(10)
    
List.heapify:
  description: >
    Converts a list into a heap.
  return:
    type: 'Void'
    description: >
      Nothing.
  args:
    list:
      type: '@[T]'
      description: >
        The mutable reference to the list to be heapified.
    by:
      type: 'func(x,y:&T->Int32)'
      default: 'T.compare'
      description: >
        The comparison function used to determine order. If not specified, the
        default comparison function for the item type will be used.
  example: |
    >> my_heap := [30, 10, 20]
    >> my_heap.heapify()
    
List.insert:
  description: >
    Inserts an element at a specified position in the list.
  return:
    type: 'Void'
    description: >
      Nothing.
  args:
    list:
      type: '@[T]'
      description: >
        The mutable reference to the list.
    item:
      type: 'T'
      description: >
        The item to be inserted.
    at:
      type: 'Int'
      default: '0'
      description: >
        The index at which to insert the item.
  note: >
    Since indices are 1-indexed and negative indices mean "starting from the
    back", an index of `0` means "after the last item".
  example: |
    >> list := [10, 20]
    >> list.insert(30)
    >> list
    = [10, 20, 30]
    
    >> list.insert(999, at=2)
    >> list
    = [10, 999, 20, 30]
    
List.insert_all:
  description: >
    Inserts a list of items at a specified position in the list.
  return:
    type: 'Void'
    description: >
      Nothing.
  args:
    list:
      type: '@[T]'
      description: >
        The mutable reference to the list.
    items:
      type: '[T]'
      description: >
        The items to be inserted.
    at:
      type: 'Int'
      default: '0'
      description: >
        The index at which to insert the item.
  note: >
    Since indices are 1-indexed and negative indices mean "starting from the
    back", an index of `0` means "after the last item".
  example: |
    list := [10, 20]
    list.insert_all([30, 40])
    >> list
    = [10, 20, 30, 40]
    
    list.insert_all([99, 100], at=2)
    >> list
    = [10, 99, 100, 20, 30, 40]
    
List.pop:
  description: >
    Removes and returns an item from the list. If the given index is present in
    the list, the item at that index will be removed and the list will become one
    element shorter.
  return:
    type: 'T?'
    description: >
      `none` if the list is empty or the given index does not exist in the list,
      otherwise the item at the given index.
  args:
    list:
      type: '&[T]'
      description: >
        The list to remove an item from.
    index:
      type: 'Int'
      default: '-1'
      description: >
        The index from which to remove the item.
  note: >
    Since negative indices are counted from the back, the default behavior is
    to pop the last value.
  example: |
    >> list := [10, 20, 30, 40]
    
    >> list.pop()
    = 40
    >> list
    = &[10, 20, 30]
    
    >> list.pop(index=2)
    = 20
    >> list
    = &[10, 30]
    
List.random:
  description: >
    Selects a random element from the list.
  return:
    type: 'T'
    description: >
      A random element from the list.
  args:
    list:
      type: '[T]'
      description: >
        The list from which to select a random element.
    random:
      type: 'func(min,max:Int64->Int64)?'
      default: 'none'
      description: >
        If provided, this function will be used to get a random index in the list. Returned
        values must be between `min` and `max` (inclusive). (Used for deterministic pseudorandom number
        generation)
  example: |
    >> [10, 20, 30].random()
    = 20
    
List.remove_at:
  description: >
    Removes elements from the list starting at a specified index.
  return:
    type: 'Void'
    description: >
      Nothing.
  args:
    list:
      type: '@[T]'
      description: >
        The mutable reference to the list.
    at:
      type: 'Int'
      default: '-1'
      description: >
        The index at which to start removing elements.
    count:
      type: 'Int'
      default: '1'
      description: >
        The number of elements to remove.
  note: >
    Since negative indices are counted from the back, the default behavior is
    to remove the last item.
  example: |
    list := [10, 20, 30, 40, 50]
    list.remove_at(2)
    >> list
    = [10, 30, 40, 50]
    
    list.remove_at(2, count=2)
    >> list
    = [10, 50]
    
List.remove_item:
  description: >
    Removes all occurrences of a specified item from the list.
  return:
    type: 'Void'
    description: >
      Nothing.
  args:
    list:
      type: '@[T]'
      description: >
        The mutable reference to the list.
    item:
      type: 'T'
      description: >
        The item to be removed.
    max_count:
      type: 'Int'
      default: '-1'
      description: >
        The maximum number of occurrences to remove.
  note: >
    A negative `max_count` means "remove all occurrences".
  example: |
    list := [10, 20, 10, 20, 30]
    list.remove_item(10)
    >> list
    = [20, 20, 30]
    
    list.remove_item(20, max_count=1)
    >> list
    = [20, 30]
    
List.reversed:
  description: >
    Returns a reversed slice of the list.
  return:
    type: '[T]'
    description: >
      A slice of the list with elements in reverse order.
  args:
    list:
      type: '[T]'
      description: >
        The list to be reversed.
  example: |
    >> [10, 20, 30].reversed()
    = [30, 20, 10]
    
List.sample:
  description: >
    Selects a sample of elements from the list, optionally with weighted
    probabilities.
  return:
    type: '[T]'
    description: >
      A list of sampled elements from the list.
  errors: >
    Errors will be raised if any of the following conditions occurs:
    - The given list has no elements and `count >= 1`
    - `count < 0` (negative count)
    - The number of weights provided doesn't match the length of the list. 
    - Any weight in the weights list is negative, infinite, or `NaN`
    - The sum of the given weights is zero (zero probability for every element).
  args:
    list:
      type: '[T]'
      description: >
        The list to sample from.
    count:
      type: 'Int'
      description: >
        The number of elements to sample.
    weights:
      type: '[Num]?'
      default: '![Num]'
      description: >
        The probability weights for each element in the list. These
        values do not need to add up to any particular number, they are relative
        weights. If no weights are given, elements will be sampled with uniform
        probability.
    random:
      type: 'func(->Num)?'
      default: 'none'
      description: >
        If provided, this function will be used to get random values for
        sampling the list. The provided function should return random numbers
        between `0.0` (inclusive) and `1.0` (exclusive). (Used for deterministic
        pseudorandom number generation)
  example: |
    >> [10, 20, 30].sample(2, weights=[90%, 5%, 5%])
    = [10, 10]
    
List.shuffle:
  description: >
    Shuffles the elements of the list in place.
  return:
    type: 'Void'
    description: >
      Nothing.
  args:
    list:
      type: '@[T]'
      description: >
        The mutable reference to the list to be shuffled.
    random:
      type: 'func(min,max:Int64->Int64)?'
      default: 'none'
      description: >
        If provided, this function will be used to get a random index in the list. Returned
        values must be between `min` and `max` (inclusive). (Used for deterministic pseudorandom number
        generation)
  example: |
    >> list.shuffle()
    
List.shuffled:
  description: >
    Creates a new list with elements shuffled.
  return:
    type: '[T]'
    description: >
      A new list with shuffled elements.
  args:
    list:
      type: '[T]'
      description: >
        The list to be shuffled.
    random:
      type: 'func(min,max:Int64->Int64)?'
      default: 'none'
      description: >
        If provided, this function will be used to get a random index in the list. Returned
        values must be between `min` and `max` (inclusive). (Used for deterministic pseudorandom number
        generation)
  example: |
    >> [10, 20, 30, 40].shuffled()
    = [40, 10, 30, 20]
    
List.slice:
  description: >
    Returns a slice of the list spanning the given indices (inclusive).
  return:
    type: '[T]'
    description: >
      A new list spanning the given indices. Note: negative indices are counted from
      the back of the list, so `-1` refers to the last element, `-2` the
      second-to-last, and so on.
  args:
    list:
      type: '[T]'
      description: >
        The original list.
    from:
      type: 'Int'
      description: >
        The first index to include.
    to:
      type: 'Int'
      description: >
        The last index to include.
  example: |
    >> [10, 20, 30, 40, 50].slice(2, 4)
    = [20, 30, 40]
    
    >> [10, 20, 30, 40, 50].slice(-3, -2)
    = [30, 40]
    
List.sort:
  description: >
    Sorts the elements of the list in place in ascending order (small to large).
  return:
    type: 'Void'
    description: >
      Nothing.
  args:
    list:
      type: '@[T]'
      description: >
        The mutable reference to the list to be sorted.
    by:
      default: 'T.compare'
      description: >
        The comparison function used to determine order. If not specified, the
        default comparison function for the item type will be used.
  example: |
    list := [40, 10, -30, 20]
    list.sort()
    >> list
    = [-30, 10, 20, 40]
    
    list.sort(func(a,b:&Int): a.abs() <> b.abs())
    >> list
    = [10, 20, -30, 40]
    
List.sorted:
  description: >
    Creates a new list with elements sorted.
  return:
    type: '[T]'
    description: >
      A new list with sorted elements.
  args:
    list:
      type: '[T]'
      description: >
        The list to be sorted.
    by:
      default: 'T.compare'
      description: >
        The comparison function used to determine order. If not specified, the
        default comparison function for the item type will be used.
  example: |
    >> [40, 10, -30, 20].sorted()
    = [-30, 10, 20, 40]
    
    >> [40, 10, -30, 20].sorted(func(a,b:&Int): a.abs() <> b.abs())
    = [10, 20, -30, 40]
    
List.to:
  description: >
    Returns a slice of the list from the start of the original list up to a specified index (inclusive).
  return:
    type: '[T]'
    description: >
      A new list containing elements from the start up to the specified index.
  args:
    list:
      type: '[T]'
      description: >
        The original list.
    last:
      type: 'Int'
      description: >
        The index up to which elements should be included.
  example: |
    >> [10, 20, 30, 40, 50].to(3)
    = [10, 20, 30]
    
    >> [10, 20, 30, 40, 50].to(-2)
    = [10, 20, 30, 40]
    
List.unique:
  description: >
    Returns a Set that contains the unique elements of the list.
  return:
    type: '|T|'
    description: >
      A set containing only unique elements from the list.
  args:
    list:
      type: '[T]'
      description: >
        The list to process.
  example: |
    >> [10, 20, 10, 10, 30].unique()
    = {10, 20, 30}