Python: How to remove a list containing Nones from a list of lists?

Question

I have something like this:

myList = [[1, None, None, None, None],[2, None, None, None, None],[3, 4, None, None, None]]

And if any of the lists in the list have 4 Nones, I want to remove them so the output is:

myList = [[3, 4, None, None, None]]

I tried using:

for l in myList:
    if(l.count(None) == 4):
        myList.remove(l)

But that consistently only removes half of them, even though I know the if statement is executing correctly resulting in this:

[[2, None, None, None, None], [3, 4, None, None, None]] 

I managed to get it to work using this, but it can't be right:

for l in myList:
    if(l.count(None) == 4):
        del l[0]
        del l[0]
        del l[0]
        del l[0]
        del l[0]

myList = list(filter(None, myList))

What's a better way of doing this? Thanks in advance. I'm using python 3.3.

Answer 1

You could do it as:

my_new_list = [i for i in myList if i.count(None) < 4]

[OUTPUT]
[[3, 4, None, None, None]]

The problem is that you are modifying your list while iterating through it. If you want to use that kind of loop structure, do it as this instead:

i = 0
while i < len(myList):
    if(myList[i].count(None) >= 4):
        del myList[i]
    else:
        i += 1