# NumPy - Array Creation Routines

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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

### Example

The following code shows an example of an empty array.

```import numpy as np
x = np.empty([3,2], dtype = int)
print x
```

The output is as follows −

```[[22649312    1701344351]
[1818321759  1885959276]
[16779776    156368896]]
```

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

### Example 1

```# array of five zeros. Default dtype is float
import numpy as np
x = np.zeros(5)
print x
```

The output is as follows −

```[ 0.  0.  0.  0.  0.]
```

### Example 2

```import numpy as np
x = np.zeros((5,), dtype = np.int)
print x
```

Now, the output would be as follows −

```[0  0  0  0  0]
```

### Example 3

```# custom type
import numpy as np
x = np.zeros((2,2), dtype = [('x', 'i4'), ('y', 'i4')])
print x
```

It should produce the following output −

```[[(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

### Example 1

```# array of five ones. Default dtype is float
import numpy as np
x = np.ones(5)
print x
```

The output is as follows −

```[ 1.  1.  1.  1.  1.]
```

### Example 2

```import numpy as np
x = np.ones([2,2], dtype = int)
print x
```

Now, the output would be as follows −

```[[1  1]
[1  1]]
```
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