Re: Python code for testing well parenthesized expression

[Martin P. Hellwig]

candide wrote:
To add to your implementations; a readable version:
+++file parantheses.py+++
"""Parentheses Module Test"""

def parentheses_are_paired(input_string):
    "Check if 'input_string' contains paired parentheses, if so return 
True."
    parenthesis_count = 0
    parenthesis_open = '('
    parenthesis_close = ')'

    for character in input_string:
        if character == parenthesis_open:
            parenthesis_count += 1
        elif character == parenthesis_close:
            parenthesis_count -= 1


    if parenthesis_count == 0:
        return(True)
    else:
        if parenthesis_count < 0:
            error_text = 'More closing parantheses than opening ones'

        elif parenthesis_count > 0:
            error_text = 'More opening parantheses than closing ones'

        raise(ValueError(error_text))

if __name__ == '__main__':
    TEST_TRUE = 'zx4er(1(er(Yy)ol)ol)ik'
    TEST_ERROR = 'zx(4er(1(er(Yy)ol)ol)ik'

    print(parentheses_are_paired(TEST_TRUE))

    try:
        print(parentheses_are_paired(TEST_ERROR))
    except(ValueError):
        print(False)

---file parantheses.py---

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