def is_valid_math_expression(obj: str, algebraic: bool) -> bool:
"""Checks if the given obj (a string) represents a valid algebraic or
numeric expression. Note that purely-numeric expressions are NOT
considered valid algebraic expressions.
Args:
obj: str. The given math expression string.
algebraic: bool. True if the given expression is algebraic
else numeric.
Returns:
bool. Whether the given object is a valid expression.
"""
if len(obj) == 0:
return True
if not expression_parser.is_valid_expression(
obj): # type: ignore[no-untyped-call]
return False
expression_is_algebraic = expression_parser.is_algebraic(
obj) # type: ignore[no-untyped-call]
# If the algebraic flag is true, expression_is_algebraic should
# also be true, otherwise both should be false which would imply
# that the expression is numeric.
return not algebraic ^ expression_is_algebraic
def test_is_algebraic(self):
"""Tests for is_algebraic method."""
self.assertTrue(expression_parser.is_algebraic('a^2.3'))
self.assertTrue(expression_parser.is_algebraic('abs(alpha)'))
self.assertTrue(expression_parser.is_algebraic('alpha/gamma'))
self.assertTrue(expression_parser.is_algebraic('A + 2/3'))
# The following tests might seem as invalid but the individual letters
# will be joined via '*' during tokenization which makes them valid.
self.assertTrue(expression_parser.is_algebraic('Alpha'))
self.assertTrue(expression_parser.is_algebraic('invalid + 2'))
self.assertTrue(expression_parser.is_algebraic('alpha + bet/22'))
self.assertFalse(expression_parser.is_algebraic('1 + 2'))
self.assertFalse(expression_parser.is_algebraic('1^2^3/4'))
self.assertFalse(expression_parser.is_algebraic('1'))
self.assertFalse(expression_parser.is_algebraic('sqrt(4/4)'))
self.assertFalse(expression_parser.is_algebraic('tan(30)'))
with self.assertRaisesRegexp(Exception, 'Invalid bracket pairing.'):
expression_parser.is_algebraic('1 +2)')
with self.assertRaisesRegexp(Exception, 'Invalid character: ~.'):
expression_parser.is_algebraic('a~2')
with self.assertRaisesRegexp(Exception, 'Invalid character: !.'):
expression_parser.is_algebraic('4! 2')
with self.assertRaisesRegexp(Exception, 'Invalid token: ..'):
expression_parser.is_algebraic('alpha + bet/22.3.4')
def test_is_algebraic(self):
"""Tests for is_algebraic method."""
self.assertTrue(expression_parser.is_algebraic('a^2.3'))
self.assertTrue(expression_parser.is_algebraic('abs(alpha)'))
self.assertTrue(expression_parser.is_algebraic('alpha/gamma'))
self.assertTrue(expression_parser.is_algebraic('A + 2/3'))
self.assertFalse(expression_parser.is_algebraic('1 + 2'))
self.assertFalse(expression_parser.is_algebraic('1^2^3/4'))
self.assertFalse(expression_parser.is_algebraic('1'))
self.assertFalse(expression_parser.is_algebraic('sqrt(4/4)'))
self.assertFalse(expression_parser.is_algebraic('tan(30)'))
with self.assertRaises(Exception):
expression_parser.is_algebraic('1 +2)')
with self.assertRaises(Exception):
expression_parser.is_algebraic('Alpha')
with self.assertRaises(Exception):
expression_parser.is_algebraic('invalid + 2')
with self.assertRaises(Exception):
expression_parser.is_algebraic('alpha + bet/22')
