Python: Merge list of lists with boolean item?

Question

here i need to merge list of lists with a boolean item.

Input like this

list = [[[3, [1, 2]]], [[1, [2, 3]]], False, [[4, [4, 5]]]]

And excepted result is

[[3, [1, 2]], [1, [2, 3]], False, [4, [4, 5]]]

I tried this

res = []
for x in list:
   res.append(x)
print res

Thanks in advance...

take a look a this [flatten (an irregular) list of lists in python](http://stackoverflow.com/questions/2158395/flatten-an-irregular-list-of-lists-in-python) any of the answers can be modify to only one level of nesting — Copperfield, Feb 02 '16 at 18:07

score 3 · Answer 1 · edited Feb 03 '16 at 05:07

3

You can use a list comprehension to preserve the first element of your sub lists if they are valid (if sub) otherwise the sub list itself:

>>> lst = [[[3, [1, 2]]], [[1, [2, 3]]], False, [[4, [4, 5]]]]
>>> [sub[0] if sub else sub for sub in lst]
[[3, [1, 2]], [1, [2, 3]], False, [4, [4, 5]]]

Note : Don't use python keywords and built-in type's names as your variables and object names.

As @Padraic Cunningham suggested, for a more precise way you can use isinstance():

>>> [sub[0] if isinstance(sub, list) else sub for sub in lst]
[[3, [1, 2]], [1, [2, 3]], False, [4, [4, 5]]]

edited Feb 03 '16 at 05:07

Omid

2,617
4
28
43

answered Feb 02 '16 at 17:53

Mazdak

105,000
18
159
188

What if there's a `True` in the list? – kfx Feb 02 '16 at 17:53
1

@kfx In that case we need to check it too. There might be a lot of scenario here but we are dealing with this one. – Mazdak Feb 02 '16 at 17:55
1

`if isinstance(...` would be better as if sub will return false positives – Padraic Cunningham Feb 02 '16 at 18:01
1

@PadraicCunningham Yes that's better, thanks for suggestion. – Mazdak Feb 02 '16 at 18:08

Python: Merge list of lists with boolean item?

1 Answers1