>>> a = [[1,2,3], [11,12,13], [22,33,44]]
>>> a[1][1]
12
>>> b = a[:] # копируем!
>>> b[1][1]=0
>>> b
[[1, 2, 3], [11, 0, 13], [22, 33, 44]]
>>> a
[[1, 2, 3], [11, 0, 13], [22, 33, 44]]
>>>
sudo cp -ax / /mnt/
Ключик -x обязателен, и в /mnt должна быть подмонтирована другая файловая система.<form>
....
<input type="date" id="birthday" name="birthday" value="1985-12-11">
....
</form>
cur.execute("DELETE FROM datas WHERE user_id = ? AND registered < datetime('now','-1 day')", (user_id))