Module dsa.array

Module containing array classes.

""" Module containing array classes. """

class Array:
    """ 
    A static array implementation.

    Special Methods:

        Index Operator: 
            array[index]
    
        Assignment: 
            array[index] = value
    """
    def __init__(self, contents=None, capacity: int=10):
        """ 
        Initialize the array with optional contents and a fixed capacity.

        Args:
            contents: An optional iterable to fill array with default values.
            capacity (int): The initial size of the array (default is 10)
        """
        self._array = [ None ] * capacity
        #: number of elements currently in array
        self.count = 0

        if contents:
            self.extend(contents)
        
    def append(self, element):
        """
        Append an element to the array. Raise an exception if capacity is exceeded.

        Args:
            element: The element to append.
        
        Raises:
            Exception: If the array is full.
        """
        if self.count >= self.capacity():
            raise Exception(f"Capacity Error: Maximum capacity {len(self)} reached.")

        self._array[self.count] = element
        self.count += 1

    def extend(self, array):
        """ 
        Append multiple elements from a given array.  
        
        Args:
            array: An iterable containing elements to append.

        Raises:
            Exception: If appending the elements exceeds the array's capacity.
        """
        for e in array:
            self.append(e)

    def insert(self, index: int, element):
        """ 
        Insert an element at a specified index, shifting existing elements to the right.

        Args:
            index (int): The index at which to insert the element.
            element: The element to insert.

        Raises:
            IndexError: If the index is out of bounds.        
        """
        if index < 0 or index >= self.count:
            raise IndexError

        self.shift_right(self.count, index)
        self._array[index] = element
        self.count += 1
        
    def shift_right(self, start: int, end: int):
        """
        Helper method to shift elements to the right between the specified range.

        Args:
            start (int): The starting index of the shift.
            end (int): The ending index of the shift.
        """
        for i in range(start, end, -1):
            self._array[i] = self._array[i - 1]

    def delete(self, index: int):
        """  
        Delete an element at a specified index, shifting subsequent elements to the left.

        Args:
            index (int): The index of the element to delete.

        Raises:     
            IndexError: If index is out of bounds.        
        """
        if index < 0 or index >= self.count:
            raise IndexError

        self.shift_left(index, self.count)
        self.count -= 1

    def shift_left(self, start: int, end: int):
        """
        Helper method to shift elements to the left between the specified range.

        Args:
            start (int): The starting index of the shift.
            end (int): The ending index of the shift.
        """
        for i in range(start, end):
            self._array[i] = self._array[i + 1]

    def __getitem__(self, index: int):
        """
        Retrieve the element at the specified index.

        Args:
            index (int): The index of the element.

        Returns:
            The element at the specified index.

        Raises:
            IndexError: If the index is out of bounds.
        """
        if index < 0 or index >= self.count: 
            raise IndexError
        return self._array[index]
            
    def __setitem__(self, index: int, value):
        """
        Set a new value at the specified index.

        Args:
            index (int): The index at which to set the value.
            value: The new value to assign.

        Raises:
            IndexError: If the index is out of bounds.
        """
        if index < 0 or index >= self.count: 
            raise IndexError
        self._array[index] = value
        
    def __len__(self) -> int:
        """ 
        Return the number of elements in the array.

        Returns:
            The number of elements in the array.
        """
        return self.count
    
    def is_empty(self) -> bool:
        """ 
        Check if the array is empty.

        Returns:
            True if the array is empty, False otherwise.
        """
        return self.count == 0

    def capacity(self) -> int:
        """ 
        Get the total capacity of the array.

        Returns:
            The capacity of the array.
        """
        return len(self._array)
    
    def to_list(self) -> list:
        """ 
        Convert the array's elements to a standard Python list.

        Returns:
            A list containing the elements of the array.
        """
        return self._array[:self.count]

    @classmethod
    def from_list(cls, mylist: list):
        """
        Create an array from a standard Python list.

        Args:
            mylist: A Python list to initialize the array.

        Returns:
            An instance of the Array class.
        """        
        list_instance = cls()
        list_instance.extend(mylist)
 
        return list_instance

    def __repr__(self):
        """
        Represent the array's contents, count, and capacity.

        Returns:
            A string representation of the array.
        """
        return f'{self.to_list()} Count: {self.count} Capacity: {self.capacity()}'

class DynamicArray(Array):
    """ 
    A dynamic array implementation. Capacity will adjust as needed.

    Special Methods:

        Index Operator: 
            array[index]
    
        Assignment: 
            array[index] = value
    """

    def grow(self):
        """ 
        Helper method to double the capacity of the current array.
        """
        new_size = len(self._array) * 2
        new_array = [ None ] * new_size

        # copy elements
        for i in range(len(self._array)):
            new_array[i] = self._array[i]

        self._array = new_array

    def shrink(self):
        """ 
        Helper method to halve the capacity of the current array.
        """
        new_size = len(self._array) // 2
        new_array = [ None ] * new_size
        
        # copy elements
        for i in range(new_size):
            new_array[i] = self._array[i]

        self._array = new_array

    def check_capacity(self):
        """ 
        if count >= capacity, grow the array.
        if count <= 1/4 of capacity, shrink the array.
        """
        if self.count >= len(self._array):
            self.grow()
        elif self.count * 4 <= len(self._array):
            self.shrink()

    def append(self, element):
        """
        Append an element to the array. Adjust the capacity as needed.

        Args:
            element: The element to append.
        """
        self.check_capacity()

        self._array[self.count] = element
        self.count += 1

    def extend(self, array):
        """ 
        Append multiple elements from a given array.  Adjust the capacity as needed.
        
        Args:
            array: An iterable containing elements to append.
        """
        for e in array:
            self.append(e)

    def insert(self, index: int, element):
        """  
        Insert an element at a specified index, shifting existing elements to the right. Adjust the capacity as needed.

        Args:
            index (int): The index at which to insert the element.
            element: The element to insert.
        """
        if index >= self.count or index < 0:
            raise IndexError

        self.check_capacity()

        self.shift_right(self.count, index)
        self._array[index] = element
        self.count += 1
        
    def delete(self, index: int):
        """  
        Delete an element at a specified index, shifting subsequent elements to the left. Adjust the capacity as needed.

        Args:
            index (int): The index of the element to delete.
        """
        if index >= self.count or index < 0:
            raise IndexError

        self.check_capacity()

        self.shift_left(index, self.count)
        self.count -= 1

        

Classes

class Array (contents=None, capacity: int = 10)

A static array implementation.

Special Methods:

Index Operator: 
    array[index]

Assignment: 
    array[index] = value

Initialize the array with optional contents and a fixed capacity.

Args

contents

An optional iterable to fill array with default values.

capacity : int

The initial size of the array (default is 10)

Expand source code

class Array:
    """ 
    A static array implementation.

    Special Methods:

        Index Operator: 
            array[index]
    
        Assignment: 
            array[index] = value
    """
    def __init__(self, contents=None, capacity: int=10):
        """ 
        Initialize the array with optional contents and a fixed capacity.

        Args:
            contents: An optional iterable to fill array with default values.
            capacity (int): The initial size of the array (default is 10)
        """
        self._array = [ None ] * capacity
        #: number of elements currently in array
        self.count = 0

        if contents:
            self.extend(contents)
        
    def append(self, element):
        """
        Append an element to the array. Raise an exception if capacity is exceeded.

        Args:
            element: The element to append.
        
        Raises:
            Exception: If the array is full.
        """
        if self.count >= self.capacity():
            raise Exception(f"Capacity Error: Maximum capacity {len(self)} reached.")

        self._array[self.count] = element
        self.count += 1

    def extend(self, array):
        """ 
        Append multiple elements from a given array.  
        
        Args:
            array: An iterable containing elements to append.

        Raises:
            Exception: If appending the elements exceeds the array's capacity.
        """
        for e in array:
            self.append(e)

    def insert(self, index: int, element):
        """ 
        Insert an element at a specified index, shifting existing elements to the right.

        Args:
            index (int): The index at which to insert the element.
            element: The element to insert.

        Raises:
            IndexError: If the index is out of bounds.        
        """
        if index < 0 or index >= self.count:
            raise IndexError

        self.shift_right(self.count, index)
        self._array[index] = element
        self.count += 1
        
    def shift_right(self, start: int, end: int):
        """
        Helper method to shift elements to the right between the specified range.

        Args:
            start (int): The starting index of the shift.
            end (int): The ending index of the shift.
        """
        for i in range(start, end, -1):
            self._array[i] = self._array[i - 1]

    def delete(self, index: int):
        """  
        Delete an element at a specified index, shifting subsequent elements to the left.

        Args:
            index (int): The index of the element to delete.

        Raises:     
            IndexError: If index is out of bounds.        
        """
        if index < 0 or index >= self.count:
            raise IndexError

        self.shift_left(index, self.count)
        self.count -= 1

    def shift_left(self, start: int, end: int):
        """
        Helper method to shift elements to the left between the specified range.

        Args:
            start (int): The starting index of the shift.
            end (int): The ending index of the shift.
        """
        for i in range(start, end):
            self._array[i] = self._array[i + 1]

    def __getitem__(self, index: int):
        """
        Retrieve the element at the specified index.

        Args:
            index (int): The index of the element.

        Returns:
            The element at the specified index.

        Raises:
            IndexError: If the index is out of bounds.
        """
        if index < 0 or index >= self.count: 
            raise IndexError
        return self._array[index]
            
    def __setitem__(self, index: int, value):
        """
        Set a new value at the specified index.

        Args:
            index (int): The index at which to set the value.
            value: The new value to assign.

        Raises:
            IndexError: If the index is out of bounds.
        """
        if index < 0 or index >= self.count: 
            raise IndexError
        self._array[index] = value
        
    def __len__(self) -> int:
        """ 
        Return the number of elements in the array.

        Returns:
            The number of elements in the array.
        """
        return self.count
    
    def is_empty(self) -> bool:
        """ 
        Check if the array is empty.

        Returns:
            True if the array is empty, False otherwise.
        """
        return self.count == 0

    def capacity(self) -> int:
        """ 
        Get the total capacity of the array.

        Returns:
            The capacity of the array.
        """
        return len(self._array)
    
    def to_list(self) -> list:
        """ 
        Convert the array's elements to a standard Python list.

        Returns:
            A list containing the elements of the array.
        """
        return self._array[:self.count]

    @classmethod
    def from_list(cls, mylist: list):
        """
        Create an array from a standard Python list.

        Args:
            mylist: A Python list to initialize the array.

        Returns:
            An instance of the Array class.
        """        
        list_instance = cls()
        list_instance.extend(mylist)
 
        return list_instance

    def __repr__(self):
        """
        Represent the array's contents, count, and capacity.

        Returns:
            A string representation of the array.
        """
        return f'{self.to_list()} Count: {self.count} Capacity: {self.capacity()}'

Subclasses

• DynamicArray

Static methods

def from_list(mylist: list)

Create an array from a standard Python list.

Args

mylist

A Python list to initialize the array.

Returns

An instance of the Array class.

Expand source code

@classmethod
def from_list(cls, mylist: list):
    """
    Create an array from a standard Python list.

    Args:
        mylist: A Python list to initialize the array.

    Returns:
        An instance of the Array class.
    """        
    list_instance = cls()
    list_instance.extend(mylist)

    return list_instance

Instance variables

var count

number of elements currently in array

Methods

def append(self, element)

Append an element to the array. Raise an exception if capacity is exceeded.

Args

element

The element to append.

Raises

Exception

If the array is full.

Expand source code

def append(self, element):
    """
    Append an element to the array. Raise an exception if capacity is exceeded.

    Args:
        element: The element to append.
    
    Raises:
        Exception: If the array is full.
    """
    if self.count >= self.capacity():
        raise Exception(f"Capacity Error: Maximum capacity {len(self)} reached.")

    self._array[self.count] = element
    self.count += 1

def capacity(self) ‑> int

Get the total capacity of the array.

Returns

The capacity of the array.

Expand source code

def capacity(self) -> int:
    """ 
    Get the total capacity of the array.

    Returns:
        The capacity of the array.
    """
    return len(self._array)

def delete(self, index: int)

Delete an element at a specified index, shifting subsequent elements to the left.

Args

index : int

The index of the element to delete.

Raises:
IndexError: If index is out of bounds.

Expand source code

def delete(self, index: int):
    """  
    Delete an element at a specified index, shifting subsequent elements to the left.

    Args:
        index (int): The index of the element to delete.

    Raises:     
        IndexError: If index is out of bounds.        
    """
    if index < 0 or index >= self.count:
        raise IndexError

    self.shift_left(index, self.count)
    self.count -= 1

def extend(self, array)

Append multiple elements from a given array.

Args

array

An iterable containing elements to append.

Raises

Exception

If appending the elements exceeds the array's capacity.

Expand source code

def extend(self, array):
    """ 
    Append multiple elements from a given array.  
    
    Args:
        array: An iterable containing elements to append.

    Raises:
        Exception: If appending the elements exceeds the array's capacity.
    """
    for e in array:
        self.append(e)

def insert(self, index: int, element)

Insert an element at a specified index, shifting existing elements to the right.

Args

index : int

The index at which to insert the element.

element

The element to insert.

Raises

IndexError

If the index is out of bounds.

Expand source code

def insert(self, index: int, element):
    """ 
    Insert an element at a specified index, shifting existing elements to the right.

    Args:
        index (int): The index at which to insert the element.
        element: The element to insert.

    Raises:
        IndexError: If the index is out of bounds.        
    """
    if index < 0 or index >= self.count:
        raise IndexError

    self.shift_right(self.count, index)
    self._array[index] = element
    self.count += 1

def is_empty(self) ‑> bool

Check if the array is empty.

Returns

True if the array is empty, False otherwise.

Expand source code

def is_empty(self) -> bool:
    """ 
    Check if the array is empty.

    Returns:
        True if the array is empty, False otherwise.
    """
    return self.count == 0

def shift_left(self, start: int, end: int)

Helper method to shift elements to the left between the specified range.

Args

start : int

The starting index of the shift.

end : int

The ending index of the shift.

Expand source code

def shift_left(self, start: int, end: int):
    """
    Helper method to shift elements to the left between the specified range.

    Args:
        start (int): The starting index of the shift.
        end (int): The ending index of the shift.
    """
    for i in range(start, end):
        self._array[i] = self._array[i + 1]

def shift_right(self, start: int, end: int)

Helper method to shift elements to the right between the specified range.

Args

start : int

The starting index of the shift.

end : int

The ending index of the shift.

Expand source code

def shift_right(self, start: int, end: int):
    """
    Helper method to shift elements to the right between the specified range.

    Args:
        start (int): The starting index of the shift.
        end (int): The ending index of the shift.
    """
    for i in range(start, end, -1):
        self._array[i] = self._array[i - 1]

def to_list(self) ‑> list

Convert the array's elements to a standard Python list.

Returns

A list containing the elements of the array.

Expand source code

def to_list(self) -> list:
    """ 
    Convert the array's elements to a standard Python list.

    Returns:
        A list containing the elements of the array.
    """
    return self._array[:self.count]

class DynamicArray (contents=None, capacity: int = 10)

A dynamic array implementation. Capacity will adjust as needed.

Special Methods:

Index Operator: 
    array[index]

Assignment: 
    array[index] = value

Initialize the array with optional contents and a fixed capacity.

Args

contents

An optional iterable to fill array with default values.

capacity : int

The initial size of the array (default is 10)

Expand source code

class DynamicArray(Array):
    """ 
    A dynamic array implementation. Capacity will adjust as needed.

    Special Methods:

        Index Operator: 
            array[index]
    
        Assignment: 
            array[index] = value
    """

    def grow(self):
        """ 
        Helper method to double the capacity of the current array.
        """
        new_size = len(self._array) * 2
        new_array = [ None ] * new_size

        # copy elements
        for i in range(len(self._array)):
            new_array[i] = self._array[i]

        self._array = new_array

    def shrink(self):
        """ 
        Helper method to halve the capacity of the current array.
        """
        new_size = len(self._array) // 2
        new_array = [ None ] * new_size
        
        # copy elements
        for i in range(new_size):
            new_array[i] = self._array[i]

        self._array = new_array

    def check_capacity(self):
        """ 
        if count >= capacity, grow the array.
        if count <= 1/4 of capacity, shrink the array.
        """
        if self.count >= len(self._array):
            self.grow()
        elif self.count * 4 <= len(self._array):
            self.shrink()

    def append(self, element):
        """
        Append an element to the array. Adjust the capacity as needed.

        Args:
            element: The element to append.
        """
        self.check_capacity()

        self._array[self.count] = element
        self.count += 1

    def extend(self, array):
        """ 
        Append multiple elements from a given array.  Adjust the capacity as needed.
        
        Args:
            array: An iterable containing elements to append.
        """
        for e in array:
            self.append(e)

    def insert(self, index: int, element):
        """  
        Insert an element at a specified index, shifting existing elements to the right. Adjust the capacity as needed.

        Args:
            index (int): The index at which to insert the element.
            element: The element to insert.
        """
        if index >= self.count or index < 0:
            raise IndexError

        self.check_capacity()

        self.shift_right(self.count, index)
        self._array[index] = element
        self.count += 1
        
    def delete(self, index: int):
        """  
        Delete an element at a specified index, shifting subsequent elements to the left. Adjust the capacity as needed.

        Args:
            index (int): The index of the element to delete.
        """
        if index >= self.count or index < 0:
            raise IndexError

        self.check_capacity()

        self.shift_left(index, self.count)
        self.count -= 1

Ancestors

• Array

Methods

def append(self, element)

Append an element to the array. Adjust the capacity as needed.

Args

element

The element to append.

Expand source code

def append(self, element):
    """
    Append an element to the array. Adjust the capacity as needed.

    Args:
        element: The element to append.
    """
    self.check_capacity()

    self._array[self.count] = element
    self.count += 1

def check_capacity(self)

if count >= capacity, grow the array. if count <= 1/4 of capacity, shrink the array.

Expand source code

def check_capacity(self):
    """ 
    if count >= capacity, grow the array.
    if count <= 1/4 of capacity, shrink the array.
    """
    if self.count >= len(self._array):
        self.grow()
    elif self.count * 4 <= len(self._array):
        self.shrink()

def delete(self, index: int)

Delete an element at a specified index, shifting subsequent elements to the left. Adjust the capacity as needed.

Args

index : int

The index of the element to delete.

Expand source code

def delete(self, index: int):
    """  
    Delete an element at a specified index, shifting subsequent elements to the left. Adjust the capacity as needed.

    Args:
        index (int): The index of the element to delete.
    """
    if index >= self.count or index < 0:
        raise IndexError

    self.check_capacity()

    self.shift_left(index, self.count)
    self.count -= 1

def extend(self, array)

Append multiple elements from a given array. Adjust the capacity as needed.

Args

array

An iterable containing elements to append.

Expand source code

def extend(self, array):
    """ 
    Append multiple elements from a given array.  Adjust the capacity as needed.
    
    Args:
        array: An iterable containing elements to append.
    """
    for e in array:
        self.append(e)

def grow(self)

Helper method to double the capacity of the current array.

Expand source code

def grow(self):
    """ 
    Helper method to double the capacity of the current array.
    """
    new_size = len(self._array) * 2
    new_array = [ None ] * new_size

    # copy elements
    for i in range(len(self._array)):
        new_array[i] = self._array[i]

    self._array = new_array

def insert(self, index: int, element)

Insert an element at a specified index, shifting existing elements to the right. Adjust the capacity as needed.

Args

index : int

The index at which to insert the element.

element

The element to insert.

Expand source code

def insert(self, index: int, element):
    """  
    Insert an element at a specified index, shifting existing elements to the right. Adjust the capacity as needed.

    Args:
        index (int): The index at which to insert the element.
        element: The element to insert.
    """
    if index >= self.count or index < 0:
        raise IndexError

    self.check_capacity()

    self.shift_right(self.count, index)
    self._array[index] = element
    self.count += 1

def shrink(self)

Helper method to halve the capacity of the current array.

Expand source code

def shrink(self):
    """ 
    Helper method to halve the capacity of the current array.
    """
    new_size = len(self._array) // 2
    new_array = [ None ] * new_size
    
    # copy elements
    for i in range(new_size):
        new_array[i] = self._array[i]

    self._array = new_array

Inherited members

• Array:
  • capacity
  • count
  • from_list
  • is_empty
  • shift_left
  • shift_right
  • to_list