[Python] Processing Python 2D list with for loops [duplicate]

I wrote the following code:

Test=[[0.0]*4]*4
for r in range(4):
for m in range(4):
Test[r][m] = m+r
print(r,m,Test[r][m])
print(Test)


Why finally all rows within the list contain the values from the last "r" iteration, i.e.:

[[3, 4, 5, 6], [3, 4, 5, 6], [3, 4, 5, 6], [3, 4, 5, 6]]


instead of

[[0. 1. 2. 3.], [1. 2. 3. 4.], [2. 3. 4. 5.], [3. 4. 5. 6.]]


which is generated when numpy 2D array is used?

Continue reading...