so whats the difference between:
x = [1,1,1], [1,1,1], [1,1,1], [1,1,1] and
x = [[1,1,1], [1,1,1], [1,1,1], [1,1,1]] do the square brackets around the second option do anything?
- 3First one will create a tuple of lists, second one will create a list of lists.thefourtheye– thefourtheye2015-07-14 10:04:18 +00:00Commented Jul 14, 2015 at 10:04
- 3@AvinashRaj both examples workvaultah– vaultah2015-07-14 10:04:23 +00:00Commented Jul 14, 2015 at 10:04
- 2Did you try printing both to see what you had?Padraic Cunningham– Padraic Cunningham2015-07-14 10:09:55 +00:00Commented Jul 14, 2015 at 10:09
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4 Answers
x = [1,1,1], [1,1,1], [1,1,1], [1,1,1] Will create a tuple with lists
x = [[1,1,1], [1,1,1], [1,1,1], [1,1,1]] Will create lists of list
i.e.)
x = [1,1,1], [1,1,1], [1,1,1], [1,1,1] x ([1, 1, 1], [1, 1, 1], [1, 1, 1], [1, 1, 1]) type(x) <type 'tuple'> "a","b" ('a', 'b') 
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The first one creates a tuple of lists , while the second one creates a list of lists.
tuples are immutable, whereas lists are mutable.
Example for 1st one -
>>> x = [1,1,1], [1,1,1], [1,1,1], [1,1,1] >>> x ([1, 1, 1], [1, 1, 1], [1, 1, 1], [1, 1, 1]) >>> x[0] = 1 Traceback (most recent call last): File "<stdin>", line 1, in <module> TypeError: 'tuple' object does not support item assignment Example for 2nd one -
>>> x = [[1,1,1], [1,1,1], [1,1,1], [1,1,1]] >>> x [[1, 1, 1], [1, 1, 1], [1, 1, 1], [1, 1, 1]] >>> x[0] = 1 >>> x [1, [1, 1, 1], [1, 1, 1], [1, 1, 1]] 
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Without the brackets it is a tuple:
>>> x = [1,1,1], [1,1,1], [1,1,1], [1,1,1] >>> x ([1, 1, 1], [1, 1, 1], [1, 1, 1], [1, 1, 1]) >>> type(x) <type 'tuple'> You can't modify the items in a tuple.
With [] is it a list:
>>> x = [[1,1,1], [1,1,1], [1,1,1], [1,1,1]] >>> x [[1, 1, 1], [1, 1, 1], [1, 1, 1], [1, 1, 1]] >>> type(x) <type 'list'> 
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The first one is the same as doing this :
x = ([1,1,1], [1,1,1], [1,1,1], [1,1,1])
This is a tuple of lists.
