Comprehending a list comprehension!

[buran]

If device.data is a list, data = [b for b in device.data] is meaningless. It's the same as data = device.data.

That is not true. List is mutable, thus is you just do data = device.data change in data would affect also device.data and vice versa.

>>> my_list = [1, 2, 3]
>>> a_list = [x for x in my_list]
>>> b_list = my_list
>>> my_list[0] = 100
>>> my_list
[100, 2, 3]
>>> a_list # still has the original values
[1, 2, 3]
>>> b_list
[100, 2, 3] # has new value at index 0, same as my_list
>>>

an alternative to list comprehension for creating a copy would be list slicing

data = device.data[::]