numpy.zeros() & numpy.ones() | Create a numpy array of zeros or ones

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Create a 1D / 2D Numpy Arrays of zeros or ones

We are going to how we can create variou types of numpy arrays.

numpy.zeros( ) :

The numpy module in python makes it able to create a numpy array all initialized with 0’s.

Syntax: numpy.zeros(shape, dtype=, order=)

Parameters :

  1. shape : The shape of the numpy array.(single Int or a sequence)
  2. dtype : It is an optional parameter that takes the data type of elements.(default value is float32)
  3. order : It is also an optional parameter which defines the order in which the array will be stored(‘C’ for column-major which is also the default value and ‘F’ for row-major)

Flattened numpy array filled with all zeros :

Below code is the implementation for that.

import numpy as np

#Creating a numpy array containing all 0's
zeroArray = np.zeros(5)
print("The array contents are : ", zeroArray)

Output : 
The array contents are :  [0. 0. 0. 0. 0.]

Creating a 2D numpy array with 5 rows & 6 columns, filled with 0’s :

To create an array with 5 rows and 6 columns filled with all 0’s, we need to pass 5 and 6 as parameters into the function.

Below code is the implementation for that.

import numpy as np

# Creating a 5X6 numpy array containing all 0's
zeroArray = np.zeros((5, 6))
print("The array contents are : ", zeroArray)

Output :
The array contents are :  [[0. 0. 0. 0. 0. 0.]
 [0. 0. 0. 0. 0. 0.]
 [0. 0. 0. 0. 0. 0.]
 [0. 0. 0. 0. 0. 0.]
 [0. 0. 0. 0. 0. 0.]]

It created a zero numpy array of 5X6 size for us.

numpy.ones( ) :

Just like the numpy.zeros( ), numpy.ones( ) is used to initialize the array elements to 1. It has same syntax.

Syntax - numpy.ones(shape, dtype=float, order='C')

Creating a flattened numpy array filled with all Ones :

Below code is the implementation for that.

import numpy as np

# Creating a numpy array containing all 1's
oneArray = np.ones(5)
print("The array contents are : ", oneArray)

Output :
The array contents are :  [1. 1. 1. 1. 1.]

Creating a 2D numpy array with 3 rows & 4 columns, filled with 1’s :

To create a 2D numpy array with 3 rows and 4 columns filled with 1’s, we have to pass (3,4) into the function.

Below code is the implementation for that.

import numpy as np

# Creating a 3X4 numpy array containing all 1's
oneArray = np.ones((3, 4))
print("The array contents are : ", oneArray)
print("Data Type of elements in  Array : ", oneArray.dtype)

Output :
The array contents are :  [[1. 1. 1. 1.]
 [1. 1. 1. 1.]
 [1. 1. 1. 1.]]
Data Type of elements in  Array :  float64

Let’s see how we can set the datatype to integer.

import numpy as np

# Creating a 3X4 numpy array containing all 1's int64 datatype
oneArray = np.ones((3, 4), dtype=np.int64)
print("The array contents are : ", oneArray)
print("Data Type of elements in  Array : ", oneArray.dtype)

Output :
The array contents are :  [[1 1 1 1]
 [1 1 1 1]
 [1 1 1 1]]
Data Type of elements in  Array :  int64