Python | Flatten a 2d numpy array into 1d array Last Updated : 03 Feb, 2023 Comments Improve Suggest changes Like Article Like Report Given a 2d numpy array, the task is to flatten a 2d numpy array into a 1d array. Below are a few methods to solve the task. Method #1 : Using np.flatten() Python3 # Python code to demonstrate # flattening a 2d numpy array # into 1d array import numpy as np ini_array1 = np.array([[1, 2, 3], [2, 4, 5], [1, 2, 3]]) # printing initial arrays print("initial array", str(ini_array1)) # Multiplying arrays result = ini_array1.flatten() # printing result print("New resulting array: ", result) Output:initial array [[1 2 3] [2 4 5] [1 2 3]] New resulting array: [1 2 3 2 4 5 1 2 3] Time complexity: O(n), where n is the total number of elements in the 2D numpy array.Auxiliary space: O(n), as the result array is also of size n. The flatten function returns a flattened 1D array, which is stored in the "result" variable. Method #2: Using np.ravel() Python3 # Python code to demonstrate # flattening a 2d numpy array # into 1d array import numpy as np ini_array1 = np.array([[1, 2, 3], [2, 4, 5], [1, 2, 3]]) # printing initial arrays print("initial array", str(ini_array1)) # Multiplying arrays result = ini_array1.ravel() # printing result print("New resulting array: ", result) Output:initial array [[1 2 3] [2 4 5] [1 2 3]] New resulting array: [1 2 3 2 4 5 1 2 3] Method #3: Using np.reshape() Python3 # Python code to demonstrate # flattening a 2d numpy array # into 1d array import numpy as np ini_array1 = np.array([[1, 2, 3], [2, 4, 5], [1, 2, 3]]) # printing initial arrays print("initial array", str(ini_array1)) # Multiplying arrays result = ini_array1.reshape([1, 9]) # printing result print("New resulting array: ", result) Output:initial array [[1 2 3] [2 4 5] [1 2 3]] New resulting array: [[1 2 3 2 4 5 1 2 3]] Time Complexity: O(n), where n is the total number of elements in the 2D numpy array.Auxiliary Space: O(n), as the program creates a new 1D list with the same number of elements as the original 2D array. Comment More infoAdvertise with us Next Article NumPy | Multiply 2D Array to 1D Array G garg_ak0109 Follow Improve Article Tags : Python Python-numpy Python numpy-program Practice Tags : python Similar Reads Convert 2D float array to 2D int array in NumPy Converting a 2D float array to a 2D integer array in NumPy is a straightforward process using the astype() method. This conversion can be useful in various data analysis and scientific computing tasks where integer data types are required or where memory efficiency is essential. In this article, we 8 min read Convert a 1D array to a 2D Numpy array Here we will learn how to convert 1D NumPy to 2D NumPy Using two methods. Numpy is a Python package that consists of multidimensional array objects and a collection of operations or routines to perform various operations on the array and processing of the array. Convert a 1D array to a 2D Numpy arr 3 min read NumPy | Multiply 2D Array to 1D Array Given two NumPy arrays, the task is to multiply a 2D array with a 1D array, each row corresponding to one element in NumPy. You can follow these methods to multiply a 1D array into a 2D array in NumPy: Using np.newaxis()Using axis as noneUsing transpose()Let's understand them better with Python prog 2 min read NumPy | Multiply 2D Array to 1D Array Given two NumPy arrays, the task is to multiply a 2D array with a 1D array, each row corresponding to one element in NumPy. You can follow these methods to multiply a 1D array into a 2D array in NumPy: Using np.newaxis()Using axis as noneUsing transpose()Let's understand them better with Python prog 2 min read numpy.atleast_2d() in Python numpy.atleast_2d() function is used when we want to Convert inputs to arrays with at least two dimension. Scalar and 1-dimensional inputs are converted to 2-dimensional arrays, whilst higher-dimensional inputs are preserved. Syntax : numpy.atleast_2d(*arrays) Parameters : arrays1, arrays2, ... : [ar 2 min read NumPy Array in Python NumPy (Numerical Python) is a powerful library for numerical computations in Python. It is commonly referred to multidimensional container that holds the same data type. It is the core data structure of the NumPy library and is optimized for numerical and scientific computation in Python. Table of C 2 min read Like