Module csv_lua.sym

Sym module deals with symbolic columns of a CSV

"""Sym module deals with symbolic columns of a CSV"""

import math


class Sym:
    """
    Sym summarizes a stream of symbols.
    """

    size: int
    """Number of symbols held"""
    col_pos: int
    """Position of symbolic column"""
    name: str
    """Name of the symbolic column"""
    _has: dict
    """Counts of occurrence for each symbol"""

    def __init__(self, col_pos=0, name="") -> None:
        self.size = 0
        self.col_pos = int(col_pos)
        self.name = name
        self._has = {}

    def add(self, symbol: str) -> None:
        """Add method adds a symbol to stream."""
        if symbol != "?":
            self.size += 1
            self._has[symbol] = self._has.get(symbol, 0) + 1

    def mid(self) -> str:
        """Mid method calculates the middle of the symbol stream."""
        most = -1
        mode = None
        for key, count in self._has.items():
            if count > most:
                mode = key
                most = count
        return mode

    def div(self) -> float:
        """Div method calculates the diversity of the symbol stream."""
        entropy = 0
        for _, count in self._has.items():
            if count > 0:
                probability = count / self.size
                entropy -= probability * math.log2(probability)
        return entropy

Classes

class Sym (col_pos=0, name='')

Sym summarizes a stream of symbols.

Expand source code

class Sym:
    """
    Sym summarizes a stream of symbols.
    """

    size: int
    """Number of symbols held"""
    col_pos: int
    """Position of symbolic column"""
    name: str
    """Name of the symbolic column"""
    _has: dict
    """Counts of occurrence for each symbol"""

    def __init__(self, col_pos=0, name="") -> None:
        self.size = 0
        self.col_pos = int(col_pos)
        self.name = name
        self._has = {}

    def add(self, symbol: str) -> None:
        """Add method adds a symbol to stream."""
        if symbol != "?":
            self.size += 1
            self._has[symbol] = self._has.get(symbol, 0) + 1

    def mid(self) -> str:
        """Mid method calculates the middle of the symbol stream."""
        most = -1
        mode = None
        for key, count in self._has.items():
            if count > most:
                mode = key
                most = count
        return mode

    def div(self) -> float:
        """Div method calculates the diversity of the symbol stream."""
        entropy = 0
        for _, count in self._has.items():
            if count > 0:
                probability = count / self.size
                entropy -= probability * math.log2(probability)
        return entropy

Class variables

var col_pos : int

Position of symbolic column

var name : str

Name of the symbolic column

var size : int

Number of symbols held

Methods

def add(self, symbol: str) ‑> None

Add method adds a symbol to stream.

Expand source code

def add(self, symbol: str) -> None:
    """Add method adds a symbol to stream."""
    if symbol != "?":
        self.size += 1
        self._has[symbol] = self._has.get(symbol, 0) + 1

def div(self) ‑> float

Div method calculates the diversity of the symbol stream.

Expand source code

def div(self) -> float:
    """Div method calculates the diversity of the symbol stream."""
    entropy = 0
    for _, count in self._has.items():
        if count > 0:
            probability = count / self.size
            entropy -= probability * math.log2(probability)
    return entropy

def mid(self) ‑> str

Mid method calculates the middle of the symbol stream.

Expand source code

def mid(self) -> str:
    """Mid method calculates the middle of the symbol stream."""
    most = -1
    mode = None
    for key, count in self._has.items():
        if count > most:
            mode = key
            most = count
    return mode