CODEWITHSUNDEEP
pythonarraysnumpymatrix
InquisitiveInquirer
InquisitiveInquirer

Reputation: 219

Python: reshaping matrix to vector of specific form

I have a 2x4 matrix of the form:

m = [[1,2,3,4],
     [5,6,7,8]]

an I'm trying to get an 8x1 vector of the form:

m_new = [1,5,2,6,3,7,4,8]

Would the reshape() function be able to do something like this? Using

m_new = m.reshape(8,1)

unfortunately doesn't seem to do the job, but hopefully there are other settings in reshape that can achieve this.

Upvotes: 1

Views: 188

Answers (1)

user3483203
user3483203

Reputation: 51165

You are looking for the order parameter, which can be applied to almost any method numpy uses to flatten multidimensional arrays.

From the documentation:

order : {‘C’, ‘F’, ‘A’}, optional

  • ‘F’ means to read / write the elements using Fortran-like index order, with the first index changing fastest, and the last index changing slowest.

Setup

m = np.arange(1, 9).reshape(-2, 4)

Examples:

m.reshape(8, order='F')

m.flatten(order='F')

m.ravel(order='F')

All result in:

array([1, 5, 2, 6, 3, 7, 4, 8])

Upvotes: 2

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