This works:
a = [[1, 2, 3], [4, 5, 6]]
nd_a = np.array(a)
So this should work too:
nd_a = np.array([[x for x in y] for y in a])
Top answer 1 of 3
21
This works:
a = [[1, 2, 3], [4, 5, 6]]
nd_a = np.array(a)
So this should work too:
nd_a = np.array([[x for x in y] for y in a])
2 of 3
11
To create a new array, it seems numpy.zeros is the way to go
import numpy as np
a = np.zeros(shape=(x, y))
You can also set a datatype to allocate it sensibly
>>> np.zeros(shape=(5,2), dtype=np.uint8)
array([[0, 0],
[0, 0],
[0, 0],
[0, 0],
[0, 0]], dtype=uint8)
>>> np.zeros(shape=(5,2), dtype="datetime64[ns]")
array([['1970-01-01T00:00:00.000000000', '1970-01-01T00:00:00.000000000'],
['1970-01-01T00:00:00.000000000', '1970-01-01T00:00:00.000000000'],
['1970-01-01T00:00:00.000000000', '1970-01-01T00:00:00.000000000'],
['1970-01-01T00:00:00.000000000', '1970-01-01T00:00:00.000000000'],
['1970-01-01T00:00:00.000000000', '1970-01-01T00:00:00.000000000']],
dtype='datetime64[ns]')
See also
- How do I create an empty array/matrix in NumPy?
- np.full(size, 0) vs. np.zeros(size) vs. np.empty()
DataCamp
campus.datacamp.com › courses › intro-to-python-for-data-science › chapter-4-numpy
2D NumPy Arrays | Python
The arrays np_height and np_weight are one-dimensional arrays, but it's perfectly possible to create 2 dimensional, three dimensional, heck even seven dimensional arrays! Let's stick to 2 in this video though. You can create a 2D numpy array from a regular Python list of lists.
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Python Guides
pythonguides.com › python-numpy-2d-array
Create A 2D NumPy Array In Python (5 Simple Methods)
May 9, 2025 - Python has no built-in 2D array type, so you use either a nested list (a list of rows, like [[1, 2], [3, 4]]) or a NumPy 2D array created with np.array(), np.zeros() and similar functions.
w3resource
w3resource.com › python-exercises › numpy › python-numpy-exercise-37.php
Python NumPy: Create a 2-dimensional array of size 2 x 3 - w3resource
August 29, 2025 - Write a NumPy program to create a 2-dimensional array of size 2 x 3 (composed of 4-byte integer elements), also print the shape, type and data type of the array. ... # Importing the NumPy library with an alias 'np' import numpy as np # Creating ...
NumPy
numpy.org › doc › 2.5 › user › basics.creation.html
Array creation — NumPy v2.5 Manual
NumPy arrays can be defined using Python sequences such as lists and tuples. Lists and tuples are defined using [...] and (...), respectively. Lists and tuples can define ndarray creation: a list of numbers will create a 1D array, a list of lists will create a 2D array, further nested lists ...
Python Examples
pythonexamples.org › python-numpy-create-2d-array
Create 2D Array in NumPy
Pass shape of the required 2D array, as a tuple, as argument to numpy.ones() function. The function returns a numpy array with specified shape, and all elements in the array initialised to ones. import numpy as np # create a 2D array with shape (3, 4) shape = (3, 4) arr = np.ones(shape) print(arr)
W3Schools
w3schools.com › python › numpy › numpy_creating_arrays.asp
NumPy Creating Arrays
NumPy is used to work with arrays. The array object in NumPy is called ndarray.
NumPy
numpy.org › doc › stable › reference › arrays.ndarray.html
The N-dimensional array (ndarray) — NumPy v2.5 Manual
The array can be indexed using Python container-like syntax: >>> # The element of x in the *second* row, *third* column, namely, 6. >>> x[1, 2] 6 · For example slicing can produce views of the array: >>> y = x[:,1] >>> y array([2, 5], dtype=int32) >>> y[0] = 9 # this also changes the corresponding element in x >>> y array([9, 5], dtype=int32) >>> x array([[1, 9, 3], [4, 5, 6]], dtype=int32) ... New arrays can be constructed using the routines detailed in Array creation routines, and also by using the low-level ndarray constructor:
NumPy
numpy.org › devdocs › user › absolute_beginners.html
NumPy: the absolute basics for beginners — NumPy v2.6.dev0 Manual
Using np.newaxis will increase the dimensions of your array by one dimension when used once. This means that a 1D array will become a 2D array, a 2D array will become a 3D array, and so on.
w3resource
w3resource.com › python-exercises › numpy › basic › numpy-basic-exercise-46.php
NumPy: Create a two-dimensional array of specified format - w3resource
Construct a 2D array with alternating row patterns and validate its structure with shape checks. Create a 2D array following a defined format and then reshape it into a flat array.
Data Science Dojo
discuss.datasciencedojo.com › python
How to create a two-dimensional array using NumPy? - Python - Data Science Dojo Discussions
May 15, 2023 - I have comprehended multiple methods that assist me in defining a one-dimensional array using NumPy. Now, I aspire to master methods that help in developing a two-dimensional array. For this purpose, I have found one met…
Programiz
programiz.com › python-programming › numpy › ndarray-creation
NumPy N-D Array Creation (With Examples)
We saw how to create N-d NumPy arrays from Python lists. Now we'll see how we can create them from scratch. To create multidimensional arrays from scratch we use functions such as ... The np.zeros() function allows us to create N-D arrays filled with all zeros. For example, ... # create 2D array with 2 rows and 3 columns filled with zeros array1 = np.zeros((2, 3)) print("2-D Array: ") print(array1)
Finxter
blog.finxter.com › home › learn python blog › how to create a two dimensional array in python?
How To Create a Two Dimensional Array in Python? - Be on the Right Side of Change
June 11, 2022 - Numpy once again has the solution to your problem as you can use the numpy.arrange() method to reshape a list into a 2D array.
Drbeane
drbeane.github.io › python_dsci › pages › array_2d.html
2-Dimensional Arrays — Python for Data Science
Numpy provides two functions for concatenating arrays: hstack(), or horizontal stack, and vstack(), or vertical stack. As the names imply, these functions allow us to create new arrays by horizontally or vertically stacking arrays, as long as stacked arrays have the same sizes along the dimension ...
Sentry
sentry.io › sentry answers › python › define a two-dimensional array in python
Python Define a Two-Dimensional Array or Matrix | Sentry
June 15, 2023 - The following code will create a 3-by-3 2D array with all values set to zero: import numpy matrix = numpy.zeros((3,3)) # array([[0., 0., 0.], # [0., 0., 0.], # [0., 0., 0.]])
OpenGenus
iq.opengenus.org › 2d-array-in-numpy
2D Arrays in NumPy (Python)
October 28, 2022 - Random Array random.rand(r,c) - this function will generate an array with all random elements.
MLJAR
mljar.com › answers › define-two-dimensional-array-python
Define two-dimensional array in Python
array[2][2] = 5 # valid array[7][2] = 3 # error · This way is much easier. You can use zeros function from numpy to create 2D array with all values set to zero: import numpy array = numpy.zeros((4,4)) REMEMBER Even though the second version is easier, the first one is better for this operation unless we need any matrix operations.
NumPy
numpy.org › devdocs › user › basics.creation.html
Array creation — NumPy v2.6.dev0 Manual
NumPy arrays can be defined using Python sequences such as lists and tuples. Lists and tuples are defined using [...] and (...), respectively. Lists and tuples can define ndarray creation: a list of numbers will create a 1D array, a list of lists will create a 2D array, further nested lists ...
GeeksforGeeks
geeksforgeeks.org › python › manipulating-multidimensional-arrays-in-python-numpy
Manipulating Multidimensional Arrays in Python NumPy - GeeksforGeeks
February 19, 2026 - Each nested structure represents a new dimension in the array. 1. 2D Array from List of Lists: NumPy's np.array() function can create a 2D array from a list of lists, where each sub-list represents a row in the array.