ShortHand for loop with list operation

Question

How can I write this in shorthand notion:

bigger_list=[]
for item in items:
    new_list = item.nested_items
    bigger_list += new_list

I have tried this, but it is not working

bigger_list += [item.nested_items for item in items]

Answer 1

bigger_list = [i.nested_item for i in items]

Answer 2

It looks like you are attempting to make a single "merged" bigger_list out of many smaller nested_items lists (iterables). I believe you are looking to do:

bigger_list=[]
for item in items:
    bigger_list.extend(item.nested_items)

There might be some temptation to try this via a comprehension as they tend to short and sweat:

bigger_list=[]
foo = [bigger_list.extend(item.nested_items) for item in items]

but comprehensions are for creating lists, not extending them. Don't use a comprehension like this. See : Is it Pythonic to use list comprehensions for just side effects?

If you were still very keen on using a comprehension, you could do the following but I think it is nowhere near as easy to follow as the simple for:

bigger_list = [nested_item for item in items for nested_item in item.nested_items]

If the intension is that bigger_list is to be a list of lists or that nested_items is not an iterable, then the answer by @rishin is what you want.