## Python NumPy empty array with examples

In this Python tutorial, we will discuss Python NumPy empty array with a few examples like below:

Python numpy empty array append
Python numpy array empty check
Python empty numpy array without shape
Python numpy empty 2d array
Python numpy concatenate empty array
Python numpy declare empty array
Python numpy empty string array
Python numpy empty 3d array
Python fill empty numpy array
Python Create Empty Numpy array and append rows
Python Create Empty Numpy array and append Columns

## Python numpy empty array

In this section, we will discuss Python numpy empty array, specially how to create an empty array using Python NumPy.
In this method we can easily use the function np.empty().
The Python NumPy empty() function is used to create a new array of given shape and type, without initializing entries.
To work with arrays, the python library provides a numpy empty array function. It is used to create a new empty array as per user instruction means given data type and shape of array without initializing elements.
It accepts shape and data type as arguments. If data type argument is not provided then the default data type of all Values in the returned numpy array will be float.

Syntax:

Here is the Syntax of numpy.empty()

numpy.empty
(
shape,
dtype=float,
order=’C’
)

It Consists of few parameters.

Shape: Shape of the empty array, e.g:(4,3)

dtype: its an optional parameter by default value is float.

order: Whether to store multi-dimensional data in row and column-wise.

Example:

Let’s take an example to check how to implement a numpy empty array
Basically there are two ways to check numpy empty array.
Using numpy empty array function.
Using numpy zero’s array function

## Using numpy empty array function

In this method, we implement a NumPy array empty function. But empty does not mean that the array values will be zeros.

import numpy as np

arr = np.empty(5)
print(arr)

In the above example, we implement a simple NumPy empty array and it returns uninitialized values with shape and data type.

Here is the Screenshot of the following given code

Python numpy empty array

To create a NumPy empty array, we can pass the empty list to the np.array() function and it will make the empty array.

Example:

import numpy as np

list = []
arr = np.array(list)
print(arr)

Here is the Screenshot of the following given code

Create numpy empty array

This is how to create an empty array using Python NumPy.

## Using numpy zero’s array function

In this method, we implement a numpy zero’s array function.
This function returns a new array of given shape and type, with zeros.

Syntax:

Here is the Syntax of numpy zeros() function

numpy.zeros
(
shape,
dtype = None,
order = ‘C’
)

Example:

import numpy as np

arr = np.zeros([2,2],dtype=’int’)
print(arr)

Here is the Screenshot of the following given code

Python numpy empty array by using zeros

This is how to create a NumPy array by using zeros.

## Python numpy empty array append

In this section, we will discuss Python numpy empty array append.
In this method we can easily use the function numpy.append().
The Numpy append function allows us to add new values to the end of an existing NumPy array.
This function returns a copy of the existing array with the values appended to the specified axis.
If we have an empty array and want to append new rows to it inside a loop, we can use the numpy.empty() function.
After that we can then append new rows to the empty array with numpy.append() function.

Example:

Let’s take an example to check how to implement a numpy empty array with append.

import numpy as np

arr = np.empty((0,3), int)

arr2 = np.append(arr, np.array([[2,4,5]]), axis=0)
array = np.append(arr2, np.array([[7,8,9]]), axis=0)

print(array)

In the above example first, we will create an empty array by using the function np. empty() and define its datatype. After that, we appended two rows along the 0 axes by using the function numpy.append()

Here is the Screenshot of the following given code

Python numpy empty array append

## Python numpy empty array append example

In this section, we will discuss Python numpy empty array append.
In this method we can easily use the list method to append with numpy empty array.
The list.append() function appends an element to the end of the list.
We can then convert this list to a numpy array with np.array() function.

Example:

import numpy as np

list = []
list.append([2,4,6])
list.append([9,5,7])
arr2 = np.array(list)
print(arr2)

Here is the Screenshot of the following given code

Python numpy empty array append list method

## Python numpy array empty check

If you want to check if a NumPy array is empty or not, follow an article on Check if NumPy Array is Empty in Python.

## Python empty numpy array without shape

In this section, we will discuss Python empty numpy array without shape.
In this method we can easily use the function append() to get the empty numpy array without shape.
First we will create a python list and convert that to a numpy array and take a variable y which is iterable.
It doesn’t accepts shape and datatype as an argument.

Example:

import numpy as np
y=[]
a = np.array([2,3,4,5])
for x in y:
a = np.append(a, x)
print(y)

Here is the Screenshot of the following given code

Python empty numpy array without shape

The above code we can use to create empty NumPy array without shape in Python.

## Python numpy empty 2d array

In this section, we will discuss Python numpy empty 2d array.
To create an empty 2D Numpy array we can pass the shape of the 2D array ( i.e. row & column count) as a tuple to the empty() function.
In this method we can easily use the function numpy.empty().
It accepts shape and data type as arguments.
It returns an empty 2d numpy array of rows and columns but all values in this 2d numpy array were not initialized.
In this method we did not provide datatype as an argument by default it takes value as float.

Syntax:

numpy.empty
(
shape,
dtype=float,
order=’C’
)

Example:

import numpy as np
arr = np.empty((4, 3), int)
print(‘Empty 2D Numpy array:’)
print(arr)

In the above example first, we will import the numpy library and create an empty 2d numpy array with 4 rows and 3 columns and print the result.

Here is the Screenshot of the following given code

Python numpy empty 2d array method

This is how to create an empty 2D Numpy array in Python.

## Python Create a numpy empty 2d array

To create an empty array in Numpy 2d array we use column and row in shape argument.
Let’s use these two functions to create an empty 2D Numpy array and append items to it as rows or columns.
In this method create an empty array with 3 columns or 0 rows.

Example:

import numpy as np

arr = np.empty((0, 3), int)
print(‘Empty 2D Numpy array:’)
print(arr)

Here is the Screenshot of the following given code

Python creates a numpy empty 2d array

## Python numpy concatenate empty array

In this section, we will discuss Python numpy concatenate empty array.
We need to create an array of a specific size m*n where m is the number of rows and n is number of columns filled with empty values so that when we concatenate to that array the initial values.
In this method we can easily use the function numpy.concatenate().
This function is used to join two or more given NumPy arrays along the existing axis.
The np.concatenate() function appends an element to the end of the list.
In this method we can easily use the both function np.concatenate and np.empty() to get the empty array.

Example:

import numpy as np
a = np.empty([2,2])
b = np.array([[4,5],[6,7]])
arr = np.concatenate((a,b))
print(arr)

Here is the Screenshot of the following given code

Python numpy concatenate empty array

The above code we can use to concatenate empty array in Python NumPy.

## Python numpy declare empty array

In this section, we will discuss Python numpy declare empty array.
In this method we can easily use the function numpy.empty().
The empty() function is used to create a new array of given shape and type, without initializing entries.

Syntax:

Here is the Syntax of numpy.empty()

numpy.empty
(
shape,
dtype=float,
order=’C’
)

Example:

To Declare an empty NumPy array of some specific data type, we can pass that data type as a dtype argument in the empty() function.

import numpy as np
a = np.empty([2,2], dtype= complex)
print(a)

In the above example, we will create an empty numpy array of complex numbers, we need to pass complex as dtype argument in the numpy.empty() function.

Here is the Screenshot of the following given code

Python numpy declare empty array

This is how to declare empty array using Python NumPy.

## Declare numpy empty array in Python

To create an empty NumPy array of integers, we need to pass int as dtype argument in the numpy.empty() function.

Example:

import numpy as np
a = np.empty([3,3], dtype= ‘int’)
print(a)

In the above example, we will create an empty NumPy array of integers numbers, we need to pass int as dtype argument in the NumPy.empty() function.

Here is the Screenshot of the following given code

Python numpy declare empty array integer method

This is how to create an empty NumPy array of integers.

## Python numpy empty string array

In this section, we will discuss Python numpy empty string array.
To create an empty numpy array of strings we can easily use the function numpy.empty().
To create an empty numpy array of 4 strings (with size 3), we need to pass ‘S3’ as dtype argument in the numpy.empty() function.
It accepts shape and data type as arguments.

Example:

Let’s take an example to check how to create a numpy empty string array

import numpy as np

array = np.empty(4, dtype=’S3′)
print(array)

Here ‘S3’ translates to “Unicode string of length 3

Here is the Screenshot of the following given code

Python numpy empty string array

The above code we can use to create an empty string array in Python using NumPy.

## Python numpy empty 3d array

In this section, we will discuss Python numpy empty 3d array.
To create an empty 3D Numpy array we can pass the shape of the 3D array as a tuple to the empty() function.
In this method we can easily use the function numpy.empty() to get the empty 3d array.
Let’s create a empty 3D Numpy array with matrix of 3 rows and 3 columns.
In this method we didnot provide any datatype argument. But all values in this 3D numpy array were not initialized.

Example:

import numpy as np

array = np.empty((1, 3, 3)) # where 1 is the length of matrix
print(array)

In the above example first, we will import a numpy library and create an empty array in which we assign an argument as the length of the matrix which is 1 and no of rows and columns.

Here is the Screenshot of the following given code

Python numpy empty 3d array

This is an example of a Python NumPy empty 3d array.

## Python fill empty numpy array

In this section, we will discuss Python fill empty numpy array.
In this method we can easily use the function numpy.empty().
When you create an array with np.empty, you need to specify the exact shape of the output by using the shape parameter.
Let’s create an empty array and use the function a.fill().

fill() method is used to fill the numpy array with a scalar value.
In this method we didnot need to use loops to initialize an array if we are using this fill() function.

Example:

import numpy as np

a = np.empty(4)
a.fill(3)
print(a)

Here is the Screenshot of the following given code

Python fill empty numpy array

The above code we can use to fill empty NumPy array in Python.

## Python Create an Empty Numpy array and append rows

In this section, we will discuss Empty Numpy array and append rows.
In this method, first we will create an empty numpy array with 4 columns and 0 rows.
Now to append a new row to this empty 2D Numpy array, we can use the numpy.append().
But we need to pass the row as a numpy array of same shape only, and pass axis=0, so that it can be appended along the column.

Example:

import numpy as np

arr = np.empty((0, 4), int)
print(‘Empty 2D Numpy array:’)
print(arr)
# Append a row to the 2D numpy array
emp_arr = np.append(arr, np.array([[4, 3, 6, 7]]), axis=0)
# Append 2nd rows to the 2D Numpy array
emp_arr = np.append(emp_arr, np.array([[2, 6, 9, 10]]), axis=0)
print(‘2D Numpy array:’)
print(emp_arr)

In the above example our 2D Numpy array had 4 columns, therefore to add a new row we need to pass this row as a separate 2D NumPy array with dimension (2,4).

Here is the Screenshot of the following given code

Python Create an Empty Numpy array and append rows

The above code we can use to Create an Empty Numpy array and append rows in Python.

## Python Create Empty Numpy array and append Columns

In this section, we will discuss Empty Numpy array and append columns.
In this method, first we will create an empty numpy array with 0 column and 4 rows.
Now to append a new column to this empty 2D Numpy array, we can use the numpy.append().
But we need to pass the column as a numpy array of same shape only and argument axis=1, so that it can be appended along the column.

Example:

import numpy as np

arr = np.empty((4, 0), int)
print(‘Empty 2D Numpy array:’)
print(arr)
# Column list1
emp_arr = np.append(arr, np.array([[4, 3, 6, 7]]).transpose(), axis=1)

print(‘2D Numpy array:’)
print(emp_arr)

In the above example our empty numpy array has 4 rows & 0 columns, so to add a new column we need to pass this column as a separate 2D numpy array with dimension (4,1).

Here is the Screenshot of the following given code

Python Create Empty Numpy array and append Columns

The above code we can use to create an empty Numpy array and append Columns in Python.

You may like the following Python tutorials:

In this Python tutorial, we will discuss Python NumPy empty array with a few examples like below:

Python numpy empty array append
Python numpy array empty check
Python empty numpy array without shape
Python numpy empty 2d array
Python numpy concatenate empty array
Python numpy declare empty array
Python numpy empty string array
Python numpy empty 3d array
Python fill empty numpy array
Python Create Empty Numpy array and append rows
Python Create Empty Numpy array and append Columns