A new ndarray object can be constructed by any of the following array creation routines or using a low-level ndarray constructor.
numpy.empty
It creates an uninitialized array of specified shape and dtype. It uses the following constructor −
numpy.empty(shape, dtype = float, order = 'C')
The constructor takes the following parameters.
Sr.No. | Parameter & Description |
---|---|
1 | Shape Shape of an empty array in int or tuple of int |
2 | Dtype Desired output data type. Optional |
3 | Order 'C' for C-style row-major array, 'F' for FORTRAN style column-major array |
Shape
Shape of an empty array in int or tuple of int
Dtype
Desired output data type. Optional
Order
'C' for C-style row-major array, 'F' for FORTRAN style column-major array
Example
The following code shows an example of an empty array.
import numpy as np
x = np.empty([5,5], dtype = int)
print(x)
The output is as follows −
[[-1725735032 611 64 0 0]
[ 0 0 0 0 0]
[ 926115427 1664301412 811808869 878785330 1633825330]
[ 1633759587 828715320 959658032 875979365 895759460]
[ 895837752 1697657910 1700868152 909258851 842086244]]
Note − The elements in an array show random values as they are not initialized.
numpy.zeros
Returns a new array of specified size, filled with zeros.
numpy.zeros(shape, dtype = float, order = 'C')
The constructor takes the following parameters.
Sr.No. | Parameter & Description |
---|---|
1 | Shape Shape of an empty array in int or sequence of int |
2 | Dtype Desired output data type. Optional |
3 | Order 'C' for C-style row-major array, 'F' for FORTRAN style column-major array |
Shape
Shape of an empty array in int or sequence of int
Dtype
Desired output data type. Optional
Order
'C' for C-style row-major array, 'F' for FORTRAN style column-major array
Example 1
# array of nine zeros. Default dtype is float
import numpy as np
x = np.zeros(9)
print(x)
The output is as follows −
[0. 0. 0. 0. 0. 0. 0. 0. 0.]
Example 2
import numpy as np
x = np.zeros((6,), dtype = np.int)
print(x)
Now, the output would be as follows −
[0 0 0 0 0 0]
Example 3
# custom type
import numpy as np
x = np.zeros((3,3), dtype = [('x', 'i2'), ('y', 'i2')])
print(x)
It should produce the following output −
[[(0, 0) (0, 0) (0, 0)]
[(0, 0) (0, 0) (0, 0)]
[(0, 0) (0, 0) (0, 0)]]
numpy.ones
Returns a new array of specified size and type, filled with ones.
numpy.ones(shape, dtype = None, order = 'C')
The constructor takes the following parameters.
Sr.No. | Parameter & Description |
---|---|
1 | Shape Shape of an empty array in int or tuple of int |
2 | Dtype Desired output data type. Optional |
3 | Order 'C' for C-style row-major array, 'F' for FORTRAN style column-major array |
Shape
Shape of an empty array in int or tuple of int
Dtype
Desired output data type. Optional
Order
'C' for C-style row-major array, 'F' for FORTRAN style column-major array
Example 1
# array of ten ones. Default dtype is float
import numpy as np
x = np.ones(10)
print(x)
The output is as follows −
[1. 1. 1. 1. 1. 1. 1. 1. 1. 1.]
Example 2
import numpy as np
x = np.ones([4,4], dtype = int)
print(x)
Now, the output would be as follows −
[[1 1 1 1]
[1 1 1 1]
[1 1 1 1]
[1 1 1 1]]