strings.string_is_valid_number
==============================

.. py:module:: strings.string_is_valid_number

.. autoapi-nested-parse::

   Topic: Deterministic Finite Automaton (DFA)
   Given a string s, return whether s is a valid number or not
   LeetCode link: https://leetcode.com/problems/valid-number/description/



Attributes
----------

.. autoapisummary::

   strings.string_is_valid_number.state_machine


Classes
-------

.. autoapisummary::

   strings.string_is_valid_number.CharType
   strings.string_is_valid_number.State


Functions
---------

.. autoapisummary::

   strings.string_is_valid_number.classify_char
   strings.string_is_valid_number.is_valid_number


Module Contents
---------------

.. py:class:: CharType

   Bases: :py:obj:`enum.Enum`


   Create a collection of name/value pairs.

   Example enumeration:

   >>> class Color(Enum):
   ...     RED = 1
   ...     BLUE = 2
   ...     GREEN = 3

   Access them by:

   - attribute access:

     >>> Color.RED
     <Color.RED: 1>

   - value lookup:

     >>> Color(1)
     <Color.RED: 1>

   - name lookup:

     >>> Color['RED']
     <Color.RED: 1>

   Enumerations can be iterated over, and know how many members they have:

   >>> len(Color)
   3

   >>> list(Color)
   [<Color.RED: 1>, <Color.BLUE: 2>, <Color.GREEN: 3>]

   Methods can be added to enumerations, and members can have their own
   attributes -- see the documentation for details.


   .. py:attribute:: DECIMAL
      :value: 'DECIMAL'



   .. py:attribute:: EXPONENT
      :value: 'EXPONENT'



   .. py:attribute:: NUMERIC
      :value: 'NUMERIC'



   .. py:attribute:: SIGN
      :value: 'SIGN'



.. py:class:: State

   Bases: :py:obj:`enum.Enum`


   Create a collection of name/value pairs.

   Example enumeration:

   >>> class Color(Enum):
   ...     RED = 1
   ...     BLUE = 2
   ...     GREEN = 3

   Access them by:

   - attribute access:

     >>> Color.RED
     <Color.RED: 1>

   - value lookup:

     >>> Color(1)
     <Color.RED: 1>

   - name lookup:

     >>> Color['RED']
     <Color.RED: 1>

   Enumerations can be iterated over, and know how many members they have:

   >>> len(Color)
   3

   >>> list(Color)
   [<Color.RED: 1>, <Color.BLUE: 2>, <Color.GREEN: 3>]

   Methods can be added to enumerations, and members can have their own
   attributes -- see the documentation for details.


   .. py:attribute:: EXPONENTIAL
      :value: 'EXPONENTIAL'



   .. py:attribute:: EXP_NUMBER
      :value: 'EXP_NUMBER'



   .. py:attribute:: EXP_SIGN
      :value: 'EXP_SIGN'



   .. py:attribute:: FRACTION
      :value: 'FRACTION'



   .. py:attribute:: FRACTIONAL
      :value: 'FRACTIONAL'



   .. py:attribute:: INITIAL
      :value: 'INITIAL'



   .. py:attribute:: SIGNED
      :value: 'SIGNED'



   .. py:attribute:: WHOLE
      :value: 'WHOLE'



.. py:function:: classify_char(char: str) -> CharType | None

   Classifies a character into one of the following categories:

   - 'CharType.NUMERIC': if the character is a digit (0-9)
   - 'CharType.SIGN': if the character is a plus sign (+) or a minus sign (-)
   - 'CharType.EXPONENT': if the character is an 'e' or 'E'
       (used in exponential notation)
   - 'CharType.DECIMAL': if the character is a decimal point (.)
   - None: if the character does not fit into any of the above categories
   - None: if size of char is not 1

   Parameters:
   char (str): The character to be classified

   Returns:
   CharType: The classification of the character

   >>> classify_char('2')
   <CharType.NUMERIC: 'NUMERIC'>
   >>> classify_char('-')
   <CharType.SIGN: 'SIGN'>
   >>> classify_char('e')
   <CharType.EXPONENT: 'EXPONENT'>
   >>> classify_char('.')
   <CharType.DECIMAL: 'DECIMAL'>
   >>> classify_char('')

   >>> classify_char('0')
   <CharType.NUMERIC: 'NUMERIC'>
   >>> classify_char('01')


.. py:function:: is_valid_number(number_string: str) -> bool

   This function checks if the input string represents a valid number.
   It uses a finite state machine to parse the input string,
   transitioning between states based on the character type.
   The function returns True if the input string represents a valid number,
   and False otherwise.
   A valid number is defined as a string that can be parsed into an
   integer, decimal, or exponent.
   >>> is_valid_number("2")
   True
   >>> is_valid_number("0089")
   True
   >>> is_valid_number("-0.1")
   True
   >>> is_valid_number("+3.14")
   True
   >>> is_valid_number("4.")
   True
   >>> is_valid_number("-.9")
   True
   >>> is_valid_number("2e10")
   True
   >>> is_valid_number("-90E3")
   True
   >>> is_valid_number("3e+7")
   True
   >>> is_valid_number("+6e-1")
   True
   >>> is_valid_number("53.5e93")
   True
   >>> is_valid_number("-123.456e789")
   True


   >>> is_valid_number("abc")
   False
   >>> is_valid_number("1a")
   False
   >>> is_valid_number("1e")
   False
   >>> is_valid_number("e3")
   False
   >>> is_valid_number("99e2.5")
   False
   >>> is_valid_number("--6")
   False
   >>> is_valid_number("-+3")
   False
   >>> is_valid_number("95a54e53")
   False
   >>> is_valid_number(".")
   False


.. py:data:: state_machine
   :type:  dict[State, dict[CharType, State]]