Use of eval() in local program-CodePudding

I'm making a small program with Python and openpyxl. I have created a function and I would like to reuse it according to a conditional, I have seen that eval() can be dangerous for possible exploits of attackers.

But using the eval() method in a local program, where the conditionals are not passed by the user, is it dangerous? do you have any alternative to modify my code and use it the way I want without the use of eval()?

The function have to move the values from one or multiple cols to another col/cols depending on a certain condition.

The function doesn't work now, I want to clarify myself first and then I will write it. I hope you understand what I want to do.

def move_values_between_cols(col, condition, col_values_to_change, new_col_values):
    wb = load_workbook(file_path)
    ws = wb.active

    for cell in ws[col]:
        if eval(condition):
            for pos in col_values_to_change:
                ws.cell(row=cell.row, column=new_col_values[pos]).value = cell.value

    wb.save(file_path)

Edit:

I receive 4 or 5 different types of excel sheets, all of them with the same information fields but sorted in different ways and some with extra columns. And I need them all with the same shape. I have a function for each type of excel that goes from how it is to how I want it. The condition is written by me.

Example of a function:

def type1():
    function1()
    function2()
    move_values_between_cols('A', 'cell.value is None', ['B','C'], ['D', 'F']):

def type2():
    function2()
    function3()
    move_values_between_cols('C', 'not isinstance(cell.value, str)', ['A','B'], ['D', 'F']):

CodePudding user response：

My suggestion is that you pass functions to move_values_between_cols instead of strings that need to be evaluated.

For example:

move_values_between_cols('A', lambda value: value is None, ['B','C'], ['D', 'F'])

and inside move_values_between_cols, check the condition with

if condition(cell.value):

instead of

if eval(condition):

CodePudding user response：

As suggested in the comments you could you lambda-functions instead of strings:

def move_values_between_cols(col, filter_func, col_values_to_change, new_col_values):
    wb = load_workbook(file_path)
    ws = wb.active

    for cell in ws[col]:
        if filter_func(cell):
            for pos in col_values_to_change:
                ws.cell(row=cell.row, column=new_col_values[pos]).value = cell.value

    wb.save(file_path)

def type1():
    function1()
    function2()
    move_values_between_cols('A', lambda cell: cell.value is None, ['B','C'], ['D', 'F']):

def type2():
    function2()
    function3()
    move_values_between_cols('C', lambda cell: not isinstance(cell.value, str), ['A','B'], ['D', 'F']):