[PYTHON] When creating a matrix in a list

Notes for yourself

Suppose you generate a list that has a 3x3 zero matrix as each element of the list as shown below.

A=[np.zeros((3,3))]*(3)


 Consider assigning a value to this list

In : A Out: [array([[ 0., 0., 0.], [ 0., 0., 0.], [ 0., 0., 0.]]), array([[ 0., 0., 0.], [ 0., 0., 0.], [ 0., 0., 0.]]), array([[ 0., 0., 0.], [ 0., 0., 0.], [ 0., 0., 0.]])]


 Here, substitute the value in the first row of the first element (zero matrix) as shown below.

A[0][0]=1



 After performing this operation, A becomes as follows.

In : A Out: [array([[ 1., 1., 1.], [ 0., 0., 0.], [ 0., 0., 0.]]), array([[ 1., 1., 1.], [ 0., 0., 0.], [ 0., 0., 0.]]), array([[ 1., 1., 1.], [ 0., 0., 0.], [ 0., 0., 0.]])]


 Assigned to all elements! ??
 Let's be careful……
 (Gentlely ``` np.zeros ((3,3,3)) I wonder if it should have been generated with` ``
 How smart is it when you want to create a multidimensional matrix with different numbers of elements for each element (I don't know if this kind of expression is allowed).

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