I am trying to convert a multi digit string in sublists, into sublists of single digit integers.
I would like to achieve this using simple list comprehension.

Original list:

```
# [[], ['0000000'], ['2200220'], ['2222220'], ['2200220'], ['2000020'], []]

```

Goal List:

```
# [[0, 0, 0, 0, 0, 0, 0], [2, 2, 0, 0, 2, 2, 0], [2, 2, 2, 2, 2, 2, 0], [2, 2, 0, 0, 2, 2, 0], [2, 0, 0, 0, 0, 2, 0]]

```

The following thread helped me get this far.
[List of list, converting all strings to int, Python 3](https://stackoverflow.com/questions/43951693/list-of-list-converting-all-strings-to-int-python-3)

If I use this nested list comprehension, the strings turn into a single integer.

```
mylist = [[int(i) for i in s] for s in mylist]

# [[], [0], [2200220], [2222220], [2200220], [2000020], []]

```

I was able to do what I wanted by using two steps that involved importing a module, but this is not ideal.

```
import itertools

mylist = list(itertools.chain.from_iterable(mylist))

# ['0000000', '2200220', '2222220', '2200220', '2000020']

mylist_two = [[int(i) for i in str(s)] for s in mylist]

# [[0, 0, 0, 0, 0, 0, 0], [2, 2, 0, 0, 2, 2, 0], [2, 2, 2, 2, 2, 2, 0], [2, 2, 0, 0, 2, 2, 0], [2, 0, 0, 0, 0, 2, 0]]

```

Could anyone point me in the right direction? Thank you.