Python Deque appendleft with list

Question

Hi,

I am currently creating my deque object using the following,

self.CommandList = deque((['S', False, 60],['c'],['g16'],['i50'],['r30', True],['u320'],['o5000'],['b1'],['B4500'],['W1'],['l5154'],['!10'],['p2', True, 10],['e1'],['K20'],['U0'],['Y0']))

But I wish to add a similar list to the queue later but using appendleft, so it can jump ahead of the list. I assumed the following, but had no luck.

NewList = (['S'],['c'],['!10'],['p4'],['o1200'],['i50'],['r30'],['b10'],['d1'],['A', True, 163])
self.CommandList.appendleft(NewList)

Is this even possible with appendleft??

Thank-you kindly.

Andy

Answer 1

I think you want .extendleft here. This will 'extend the list' instead of just appending the list as one element.

z = collections.deque([1,2,3,4])   # [1, 2, 3, 4]

z.appendleft(['bad', 'news'])   # [ ['bad', 'news'], 1, 2, 3, 4 ]
z.extendleft(['good', 'news'])  # [ 'good', 'news', ['bad', 'news'], 1, 2, 3, 4 ]

If they are getting inserted in reverse, the quick fix is to just reverse the list:

z.extendleft(reversed(['good', 'news']))