Changing one inner list's element changes all inner lists python : <p>Basically, this is what I've got:</p>

<pre><code>In [1]: list1 = [[0, 0, 0, 0]] * 10

In [2]: list1
Out[2]: 
[[0, 0, 0, 0],
 [0, 0, 0, 0],
 [0, 0, 0, 0],
 [0, 0, 0, 0],
 [0, 0, 0, 0],
 [0, 0, 0, 0],
 [0, 0, 0, 0],
 [0, 0, 0, 0],
 [0, 0, 0, 0],
 [0, 0, 0, 0]]

In [3]: list1[0][1] = 9

In [4]: list1
Out[4]: 
[[0, 9, 0, 0],
 [0, 9, 0, 0],
 [0, 9, 0, 0],
 [0, 9, 0, 0],
 [0, 9, 0, 0],
 [0, 9, 0, 0],
 [0, 9, 0, 0],
 [0, 9, 0, 0],
 [0, 9, 0, 0],
 [0, 9, 0, 0]]
</code></pre>

<p>When trying to change the second element of the first list to 9, I somehow changed all first elements to 9. How did this happen?</p>
