Algebraic-Expression-Parser

Control and handle any algebraic expression, as well as do common expression operations such as getting postfix, prefix, and expression tree.

Installing

pip install Algebraic-Expression-Parser

Importing

from AlgebraicExpressionParser import ExpressionParser
from AlgebraicExpressionParser import Operator
from AlgebraicExpressionParser import Operators

operators = [Operator(symbol='+'), Operator(symbol='-'), Operator(symbol='*', precedence=2), Operator(
    symbol='-', type=Operator.unary, precedence=3, associativity=Operator.rtl, position=Operator.prefix), Operator(symbol='^', precedence=4), Operator(symbol='sin', type=Operator.unary, precedence=3, associativity=Operator.rtl, position=Operator.prefix)]

operators = Operators(operators)

parser = ExpressionParser(operators)

parser.postfix('(-3) * (x^3)')

>>> ['3', '-', 'x', '3', '^', '*']

parser.postfix('sin(x)--x')

>>> ['x', 'sin', 'x', '-', '-']

parser.postfix('1^2^3')

>>> ['1', '2', '^', '3', '^']

parser.postfix('1^(2^3)')

>>> ['1', '2', '3', '^', '^']

parser.syntax_tree('(-3) * (x^3)')

>>> Node: (value: *, left: Node: (value: -, left: None, right: Node: (value: 3, left: None, right: None)), right: Node: (value: ^, left: Node: (value: x, left: None, right: None), right: Node: (value: 3, left: None, right: None)))

parser.syntax_tree('(-3) * (x^3)').preorder()

>>> ['*', '-', '3', '^', 'x', '3']

parser.syntax_tree('(-3) * (x^3)').inorder()

>>> ['-', '3', '*', 'x', '^', '3']

parser.syntax_tree('(-3) * (x^3)').postorder()

>>> ['3', '-', 'x', '3', '^', '*']

New in version 0.0.4

Escape charcter ($)

• Any charcter after it will be handled as variable even if it is a space (only one character, for variables with more than one character use special_variables parameter).
• Characters after it has higher precedence than operators.

parser.postfix('$+ + x')

>>> ['$', '+', 'x', '+']

Special Variables

• A list represents variables other than predefined ones(constants and one symbol variables)
• They have lower precedence than operators.

parser = ExpressionParser(operators, special_variables = {'_'})

parser.postfix('_ * x')

>>> ['_', 'x', '*']