On Sun, Apr 05, 2015 at 11:12:32AM -0300, Narci Edson Venturini wrote:
> The next code has an unexpected result:
>
> >>>a=3*[3*[0]]
> >>>a
> [[0, 0, 0], [0, 0, 0], [0, 0, 0]]
> >>>a[0][0]=1
> >>>a
> [[1, 0, 0], [1, 0, 0], [1, 0, 0]]
It isn't obvious, and it is *very* common for people to run into
On 05/04/15 15:12, Narci Edson Venturini wrote:
The next code has an unexpected result:
a=3*[3*[0]]
Note that this makes three references to
the list of 3 references to 0.
In other words you reference the same list 3 times.
So when you change the first copy you change the
other 2 also.
Put a
On 4/5/2015 7:12 AM, Narci Edson Venturini wrote:
The next code has an unexpected result:
a=3*[3*[0]]
a now contains three references to the same object, hence the results
you show below.
You can create three distinct objects as follows:
>>> a = [ [0,0,0] for i in (0,1,2) ]
>>> a[1][1]=1
The next code has an unexpected result:
>>>a=3*[3*[0]]
>>>a
[[0, 0, 0], [0, 0, 0], [0, 0, 0]]
>>>a[0][0]=1
>>>a
[[1, 0, 0], [1, 0, 0], [1, 0, 0]]
The code assigned to "1" a(0,0), a(1,0) and a(2,0).
It was expected: [[1, 0, 0], [0, 0, 0], [0, 0, 0]]
When the followind code is ran, them the corre
