Various data types that is supported in Numpy are listed below in the table.
To create a numpy array with various data types, we can use the dtype attribute.
In [1]: import numpy as np
In [2]: # create integer type
In [3]: np.array([5, 10, 15], dtype=np.int)
Out[3]: array([ 5, 10, 15])
In [4]: # create float type
In [5]: np.array([5, 10, 15], dtype=np.float)
Out[5]: array([ 5., 10., 15.])
In [6]: np.array([5, 10, 15], dtype=np.complex)
Out[6]: array([ 5.+0.j, 10.+0.j, 15.+0.j])It is not necessary to specify the bit size of the data type of the array. Once a numpy array is created you can not change the data type of it, however you can create a new copy of it using typecasting to change the data type.
In [7]: arr1 = np.array([5, 10, 15], dtype=np.int)
In [8]: arr2 = np.array(arr1, dtype=np.float)
In [9]: arr2.dtype
Out[9]: dtype('float64')
Or you can use the astype method of numpy array.
In [10]: arr2
Out[10]: array([ 5., 10., 15.])
In [11]: arr2.astype(np.int)
Out[11]: array([ 5, 10, 15])When doing computation with numpy array the data type might be converted from one type to another if it is required by the computation.
In [12]: arr1 = np.array([5, 10, 15], dtype=np.float)
In [13]: arr2 = np.array([5, 10, 15], dtype=np.complex)
In [14]: arr1 + arr2
Out[14]: array([10.+0.j, 20.+0.j, 30.+0.j])Real and Imaginary parts –
Regardless of the dtype of a numpy array, all numpy arrays has the attributes real and imag for extracting the real and imaginary parts of the array.
In [15]: arr3 = np.array([5, 10, 15], dtype=np.int)
In [16]: arr3.real
Out[16]: array([ 5, 10, 15])
In [17]: arr3.imag
Out[17]: array([0, 0, 0])Check numpy array data type –
To check the data type of a numpy array you can use the dtype attribute.
In [18]: arr4 = np.array([5, 10, 15])
In [19]: arr4.dtype
Out[19]: dtype('int32')