Here are two ways of creating 2d-array:
1) By
converting a list of lists (or tuples) into an array:
>>> x = N.array([[1,2,3], [4,5,6]]) >>> x array([[1, 2, 3], [4, 5, 6]])
2) Using
the zeros method to create a matrix with 5 rows and 5 columns
>>> x = N.zeros((5,5)) >>> print x [[ 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.]]
The shape of a matrix can be queried like this.
>>> x.shape (5, 5)
Individual elements can be accessed and set using this
syntax:
>>> x = N.array([[1,2,3], [4,5,6]]) >>> x[0,0] 1 >>> x[0,1] 2 >>> x[0,2] 3 >>> x[:,0] array([1, 4]) >>> x[0, :] array([1, 2, 3])
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