CODEWITHSUNDEEP
pythonnumpy
b10hazard
b10hazard

Reputation: 7809

How do I change array dimensions from one dimension to a two dimension with one column

I would like to change the shape of a numpy array from this...

[ 3803.74060338   2041.36742598   2884.96439427  17561.9569717 ]

to this...

[ [3803.74060338]   
  [2041.36742598]   
  [2884.96439427]  
  [17561.9569717] ]

I was trying np.reshape(my_array, (1,1)) but I keep getting this error...

ValueError: total size of new array must be unchanged

Is reshape what I want to do here?

Upvotes: 0

Views: 1830

Answers (2)

Harpal
Harpal

Reputation: 12587

The reasons np.shape() didn't work was because you are reshaping a 4 element array into a 1 x 1.

>>> import numpy as np
>>> a=np.array([1,2,3,4,5])
>>> a
array([1, 2, 3, 4, 5])
>>> a.reshape(len(a),1)
array([[1],
       [2],
       [3],
       [4],
       [5]])
>>>

Upvotes: 3

user2357112
user2357112

Reputation: 281381

Slice with numpy.newaxis to put additional axes into the shape of an array:

>>> my_array = numpy.array([1, 2, 3, 4, 5])
>>> my_array[:, numpy.newaxis]
array([[1],
       [2],
       [3],
       [4],
       [5]])

(numpy.newaxis is None, so you can also just use None directly. I find newaxis more readable, but it's a matter of personal preference.)

Upvotes: 2

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