python – How to convert 2D float numpy array to 2D int numpy array?

The Question :

336 people think this question is useful

How to convert real numpy array to int numpy array? Tried using map directly to array but it did not work.

The Question Comments :

The Answer 1

441 people think this answer is useful

Use the astype method.

>>> x = np.array([[1.0, 2.3], [1.3, 2.9]])
>>> x
array([[ 1. ,  2.3],
       [ 1.3,  2.9]])
>>> x.astype(int)
array([[1, 2],
       [1, 2]])

The Answer 2

70 people think this answer is useful

Some numpy functions for how to control the rounding: rint, floor,trunc, ceil. depending how u wish to round the floats, up, down, or to the nearest int.

>>> x = np.array([[1.0,2.3],[1.3,2.9]])
>>> x
array([[ 1. ,  2.3],
       [ 1.3,  2.9]])
>>> y = np.trunc(x)
>>> y
array([[ 1.,  2.],
       [ 1.,  2.]])
>>> z = np.ceil(x)
>>> z
array([[ 1.,  3.],
       [ 2.,  3.]])
>>> t = np.floor(x)
>>> t
array([[ 1.,  2.],
       [ 1.,  2.]])
>>> a = np.rint(x)
>>> a
array([[ 1.,  2.],
       [ 1.,  3.]])

To make one of this in to int, or one of the other types in numpy, astype (as answered by BrenBern):

a.astype(int)
array([[1, 2],
       [1, 3]])

>>> y.astype(int)
array([[1, 2],
       [1, 2]])

The Answer 3

18 people think this answer is useful

you can use np.int_:

>>> x = np.array([[1.0, 2.3], [1.3, 2.9]])
>>> x
array([[ 1. ,  2.3],
       [ 1.3,  2.9]])
>>> np.int_(x)
array([[1, 2],
       [1, 2]])

The Answer 4

13 people think this answer is useful

If you’re not sure your input is going to be a Numpy array, you can use asarray with dtype=int instead of astype:

>>> np.asarray([1,2,3,4], dtype=int)
array([1, 2, 3, 4])

If the input array already has the correct dtype, asarray avoids the array copy while astype does not (unless you specify copy=False):

>>> a = np.array([1,2,3,4])
>>> a is np.asarray(a)  # no copy :)
True
>>> a is a.astype(int)  # copy :(
False
>>> a is a.astype(int, copy=False)  # no copy :)
True

Add a Comment