m = 4
n = 3
flags = [[0]*n]*m
for i in range(m):
for j in range(n):
print(str(i)+","+str(j)+": ",flags)
flags[i][j] = 1
print(str(i)+","+str(j)+": ",flags)
The result is as follow.
However, my expectation on the second line is "0,0: [[1, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]"
Please correct my understanding
=> python3 test.py
0,0: [[0, 0, 0], [0, 0, 0], [0, 0, 0], [0, 0, 0]]
0,0: [[1, 0, 0], [1, 0, 0], [1, 0, 0], [1, 0, 0]]
0,1: [[1, 0, 0], [1, 0, 0], [1, 0, 0], [1, 0, 0]]
0,1: [[1, 1, 0], [1, 1, 0], [1, 1, 0], [1, 1, 0]]
0,2: [[1, 1, 0], [1, 1, 0], [1, 1, 0], [1, 1, 0]]
0,2: [[1, 1, 1], [1, 1, 1], [1, 1, 1], [1, 1, 1]]
1,0: [[1, 1, 1], [1, 1, 1], [1, 1, 1], [1, 1, 1]]
1,0: [[1, 1, 1], [1, 1, 1], [1, 1, 1], [1, 1, 1]]
...
3,2: [[1, 1, 1], [1, 1, 1], [1, 1, 1], [1, 1, 1]]
3,2: [[1, 1, 1], [1, 1, 1], [1, 1, 1], [1, 1, 1]]
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