How to append a NumPy array to an empty array in Python Last Updated : 30 Dec, 2022 Summarize Comments Improve Suggest changes Share Like Article Like Report In this article, we will cover how to append a NumPy array to an empty array in Python. Here, we will discuss 2 different methods to append into an empty NumPy array. Both of these methods differ slightly, as shown below: Append a NumPy array to an empty array using the appendExample 1 Here we are creating an empty array and then appending it to the array. Python3 import numpy as np l = np.array([]) l = np.append(l, np.array(['G', 'F', 'G'])) l = np.append(l, np.array(['G', 'F', 'G'])) print(l) Output: ['G' 'F' 'G' 'G' 'F' 'G']Example 2 Here we are creating an empty array and then appending an empty row in it to see if there is any difference. Python3 import numpy as np l = np.array([]) l = np.append(l, np.array([])) l = np.append(l, np.array(['G', 'F', 'G'])) l = np.append(l, np.array(['G', 'F', 'G'])) print(l) Output: We can see that there is no difference in output. ['G' 'F' 'G' 'G' 'F' 'G']Append a NumPy array to an empty array using hstack and vstack Here we are using the built-in functions of the NumPy library np.hstack and np.vstack. Both are very much similar to each other as they combine NumPy arrays together. The major difference is that np.hstack combines NumPy arrays horizontally and np. vstack combines arrays vertically. Python3 import numpy as np arr = np.array([]) arr = np.hstack((arr, np.array(['G', 'F', 'G']))) print(arr) arr = np.vstack((arr, np.array(['G', 'F', 'G']))) print(arr) Output: ['G' 'F' 'G'] [['G' 'F' 'G'] ['G' 'F' 'G']] Comment More infoAdvertise with us Next Article How to append a NumPy array to an empty array in Python S shlokdi35dq Follow Improve Article Tags : Numpy Similar Reads How to create an empty and a full NumPy array? Creating arrays is a basic operation in NumPy. Empty array: This array isnât initialized with any specific values. Itâs like a blank page, ready to be filled with data later. However, it will contain random leftover values in memory until you update it.Full array: This is an array where all the elem 2 min read How to Add a New Value to a NumPy Array Let's learn how to add a new value to a Numpy array. Adding elements in a NumPy array is not straightforward compared to adding them to standard Python lists. Adding Values to NumPy Array using np.append()The np.append() function is used to add new values at the end of an existing NumPy array. This 2 min read How to Create Array of zeros using Numpy in Python numpy.zeros() function is the primary method for creating an array of zeros in NumPy. It requires the shape of the array as an argument, which can be a single integer for a one-dimensional array or a tuple for multi-dimensional arrays. This method is significant because it provides a fast and memory 4 min read Modify Numpy array to store an arbitrary length string NumPy builds on (and is a successor to) the successful Numeric array object. Its goal is to create the corner-stone for a useful environment for scientific computing. NumPy provides two fundamental objects: an N-dimensional array object (ndarray) and a universal function object (ufunc). The dtype of 4 min read Different Ways to Create Numpy Arrays in Python Creating NumPy arrays is a fundamental aspect of working with numerical data in Python. NumPy provides various methods to create arrays efficiently, catering to different needs and scenarios. In this article, we will see how we can create NumPy arrays using different ways and methods. Ways to Create 3 min read Like