python nested list assignment weird behavior

[wavic]

In [1]: mat = [[0]*26]*5

In [2]: id(mat[0])
Out[2]: 140082606853896

In [3]: id(mat[1])
Out[3]: 140082606853896

As you can see the list elements are one object.
Use list comprehension instead.

mat = [0 for _ in range(26)] for range(5)]]

See this video: https://www.youtube.com/watch?v=F6u5rhUQ6dU