python_fast.py 文件源码

def make_grp_list_func(expr_str, field_names_dict, global_names_dict=None, filename=None):
    """
    >>> func = make_grp_list_func('sum(a)/cnt()', {'a': 0})
    >>> func([(1,), (2,), (3,)])
    2
    >>> func = make_grp_list_func('1+sum(a)+sum(b**2)', {'a':0, 'b':1})
    >>> func([(10, 1), (20, 2)])
    36
    >>> func = make_grp_list_func('b+sum(a)/sum(c)', {'a': 0, 'c': 1}, {'b': 0})
    >>> func([(10, 1), (20, 2), (30, 3)], [1])
    11
    >>> func = make_grp_list_func('sum(a)', {'a': 0})
    >>> func([(1,), (2,), (3,)])
    6
    """
    filename = filename or '<generated>'
    list_name = 'data'
    lambda_args = [ast.Name(id=list_name, ctx=ast.Param(), lineno=0, col_offset=0)]

    tree = ast.parse(expr_str, filename, 'eval')
    tree = RewriteCntFuncs().visit(tree)
    tree = RewriteGrpFuncs(field_names_dict).visit(tree)
    if global_names_dict:
        lambda_args.append(ast.Name(id='globaldata', ctx=ast.Param(), lineno=0, col_offset=0))
        tree = RewriteName('globaldata', global_names_dict).visit(tree)
    tree = ast.Expression(
        body = ast.Lambda(
            body=tree.body,
            args=ast.arguments(
                args=lambda_args,
                vararg=None,
                kwarg=None,
                defaults=[],
            ),
            lineno=0,
            col_offset=0,
        ),
    )
    #print ast.dump(tree)
    code = compile(tree, filename, 'eval')
    func = eval(code)
    return func