[Tutor] Generate array, different results

[Pavel Andreev]

Hello all
A question from very beginner.
I generate a simple example array and then print its elements on the screen.

f=[[0]*3]*3                      # array initialization
for i in range(3):
    for j in range(3):
        f[i][j]=str(i)+str(j)    # make simple example array
        print f[i][j],           # print resulting elements
    print '\n'


 00   01   02

 10   11   12

 20   21   22


So I generate element in loop and then print it and see all is ok.

But after that if I print the whole generated array, I see different
result with constant first number, as if "i" variable does not vary
and equals to "2". What is wrong?

>>> print f

[['20', '21', '22'], ['20', '21', '22'], ['20', '21', '22']]

I use python 2.7