```
a = [1,2,3,4]
for loop in range(0,len(a)):
    if a[loop]%2==0:
        a.remove(a[loop])
        loop = loop - 1

```

I want to reduce the list by filtering numbers which can be divided by 2. There are two questions here:

* I know this is a stupid method, is there a better (or a more pythonic) way?
* If I really want to use the for-loop to tackle this task, as the actual filtering rule for the list is more complicated than 'dividable by two', I found that the 'iterative variable' `loop` is not reduced by one as expected in `R`, how can I make it working?

### update 01

Thanks for the prompt reply, first part of the question is solved, but what about the second part? What if I want to use for-loop to deal with it and make the `loop` to be reduced by ` if the condition of 'dividable by two' is fulfilled?