Python 3: Removing an empty tuple from a list of tuples
list, python, tuples
Solution
You can filter 'empty' values:
filter(None, myList)
or you can use a list comprehension. On Python 3, `filter()` returns a generator; the list comprehension returns a list on either Python 2 or 3:
[t for t in myList if t]
If your list contains more than just tuples, you could test for empty tuples explicitly:
[t for t in myList if t != ()]
Python 2 demo:
>>> myList = [(), (), ('',), ('c', 'e'), ('ca', 'ea'), ('d',), ('do',), ('dog', 'ear', 'eat', 'cat', 'car'), ('dogs', 'cars', 'done', 'eats', 'cats', 'ears'), ('don',)]
>>> filter(None, myList)
[('',), ('c', 'e'), ('ca', 'ea'), ('d',), ('do',), ('dog', 'ear', 'eat', 'cat', 'car'), ('dogs', 'cars', 'done', 'eats', 'cats', 'ears'), ('don',)]
>>> [t for t in myList if t]
[('',), ('c', 'e'), ('ca', 'ea'), ('d',), ('do',), ('dog', 'ear', 'eat', 'cat', 'car'), ('dogs', 'cars', 'done', 'eats', 'cats', 'ears'), ('don',)]
>>> [t for t in myList if t != ()]
[('',), ('c', 'e'), ('ca', 'ea'), ('d',), ('do',), ('dog', 'ear', 'eat', 'cat', 'car'), ('dogs', 'cars', 'done', 'eats', 'cats', 'ears'), ('don',)]
Of these options, the `filter()` function is fastest:
>>> timeit.timeit('filter(None, myList)', 'from __main__ import myList')
0.637274980545044
>>> timeit.timeit('[t for t in myList if t]', 'from __main__ import myList')
1.243359088897705
>>> timeit.timeit('[t for t in myList if t != ()]', 'from __main__ import myList')
1.4746298789978027
On Python 3, stick to the list comprehension instead:
>>> timeit.timeit('list(filter(None, myList))', 'from __main__ import myList')
1.5365421772003174
>>> timeit.timeit('[t for t in myList if t]', 'from __main__ import myList')
1.29734206199646
Problem
I have a list of tuples that reads as such: ``` >>>myList [(), (), ('',), ('c', 'e'), ('ca', 'ea'), ('d',), ('do',), ('dog', 'ear', 'eat', 'cat', 'car'), ('dogs', 'cars', 'done', 'eats', 'cats', 'ears'), ('don',)] ``` And I would like it to read as such: ``` >>>myList [('',), ('c', 'e'), ('ca', 'ea'), ('d',), ('do',), ('dog', 'ear', 'eat', 'cat', 'car'), ('dogs', 'cars', 'done', 'eats', 'cats', 'ears'), ('don',)] ``` i.e. I would like to remove the empty tuples `()` from the list. While doing this I want to preserve the tuple `('',)`. I cannot seem to find a way to remove these empty tuples from the list. I have tried `myList.remove(())` and using a for loop to do it, but either that doesn't work or I am getting the syntax wrong. Any help would be appreciated.