parsing - Evaluating mathematical expressions in Python -

i want tokenize given mathematical expression parse tree this:

((3 + 4 - 1) * 5 + 6 * -7) / 2                            '/'                         /     \                        +        2                     /     \                   *         *                 /   \     /   \                -     5   6     -7              /   \             +     1           /   \          3     4 

is there pure python way this? passing string python , tree mentioned above.

thanks.

yes, python ast module provides facilities this. you'll have exact interface version of python, since ast module seems change regularly.

in particular, ast.parse() method helpful application:

>>> import ast >>> ast.parse("(1+2)*3", "", "eval") <_ast.expression object @ 0x88950> >>> ast.dump(_) 'expression(body=binop(left=binop(left=num(n=1), op=add(), right=num(n=2)), op=mult(), right=num(n=3)))'