Assignment statements in Python do not copy objects, you need to use copy():

b = a.copy()
Answer from jlesuffleur on Stack Overflow
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W3Schools
w3schools.com โ€บ python โ€บ numpy โ€บ numpy_copy_vs_view.asp
NumPy Array Copy vs View
The copy returns None. The view returns the original array. ... If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail: sales@w3schools.com ยท If you want to report an error, or if you want to make a suggestion, send us an e-mail: help@w3schools.com ยท HTML Tutorial CSS Tutorial JavaScript Tutorial How To Tutorial SQL Tutorial Python ...
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W3schools
w3schools.tech โ€บ tutorial โ€บ python โ€บ python_copy_arrays
Python - Copy Arrays - Python Arrays - W3schools
Python Arrays: Hello there, aspiring Python programmers๏ผ Today, we're going to dive into the fascinating world of copying arrays in Python. As your friendly neighborhood com...
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W3Schools
w3schools.com โ€บ python โ€บ python_lists_copy.asp
Python - Copy Lists
You can use the built-in List method copy() to copy a list. ... Another way to make a copy is to use the built-in method list(). ... You can also make a copy of a list by using the : (slice) operator.
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GeeksforGeeks
geeksforgeeks.org โ€บ python โ€บ array-copying-in-python
Array Copying in Python - GeeksforGeeks
April 30, 2025 - Changes to a affect b because both variables point to the same array. A shallow copy means constructing a new collection object and then populating it with references to the child objects found in the original. The copying process does not recurse and therefore wonโ€™t create copies of the child objects themselves.
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Tutorialspoint
tutorialspoint.com โ€บ python โ€บ python_copy_arrays.htm
Python - Copy Arrays
In Python, copying an array refers to the process of creating a new array that contains all the elements of the original array. This operation can be done using assignment operator (=) and deepcopy() method. In this chapter, we discuss how to ...
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W3Schools
w3schools.com โ€บ python โ€บ ref_list_copy.asp
Python List copy() Method
The copy() method returns a copy of the specified list. ... If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail: sales@w3schools.com
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Programiz
programiz.com โ€บ python-programming โ€บ methods โ€บ list โ€บ copy
Python List copy()
In this tutorial, we will learn about the Python List copy() method with the help of examples.
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Python
docs.python.org โ€บ 3 โ€บ library โ€บ copy.html
copy โ€” Shallow and deep copy operations
February 23, 2026 - Source code: Lib/copy.py Assignment statements in Python do not copy objects, they create bindings between a target and an object. For collections that are mutable or contain mutable items, a copy ...
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W3Schools
w3schools.com โ€บ python โ€บ python_ref_list.asp
Python List/Array Methods
Note: Python does not have built-in support for Arrays, but Python Lists can be used instead.
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NumPy
numpy.org โ€บ doc โ€บ 2.2 โ€บ reference โ€บ generated โ€บ numpy.ndarray.copy.html
numpy.ndarray.copy โ€” NumPy v2.2 Manual
>>> import copy >>> a = np.array([1, 'm', [2, 3, 4]], dtype=object) >>> c = copy.deepcopy(a) >>> c[2][0] = 10 >>> c array([1, 'm', list([10, 3, 4])], dtype=object) >>> a array([1, 'm', list([2, 3, 4])], dtype=object)
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Learning About Electronics
learningaboutelectronics.com โ€บ Articles โ€บ How-to-make-a-copy-of-an-array-in-Python.php
How to Make a Copy of an Array in Python
Using the Python copy() function, we can make a copy of an array and the copied array will contain all of the same exact elements as the original array.
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W3Schools
w3schools.com โ€บ python โ€บ python_arrays.asp
Python Arrays
Note: Python does not have built-in support for Arrays, but Python Lists can be used instead. ... If you want to use W3Schools services as an educational institution, team or enterprise, send us an e-mail: sales@w3schools.com
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NumPy
numpy.org โ€บ doc โ€บ stable โ€บ reference โ€บ generated โ€บ numpy.copy.html
numpy.copy โ€” NumPy v2.4 Manual
Note that, np.copy clears previously set WRITEABLE=False flag. >>> a = np.array([1, 2, 3]) >>> a.flags["WRITEABLE"] = False >>> b = np.copy(a) >>> b.flags["WRITEABLE"] True >>> b[0] = 3 >>> b array([3, 2, 3])
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Python Examples
pythonexamples.org โ€บ python-numpy-duplicate-copy-array
Python Numpy - Duplicate or Copy Array Data to Another Array
The array a is initialized as a 2D numpy array with two rows and three columns. The a.copy() function creates a copy of a and stores it in b.
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W3Schools
w3schools.com โ€บ python โ€บ numpy โ€บ trypython.asp
W3Schools online PYTHON editor
The W3Schools online code editor allows you to edit code and view the result in your browser
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Medium
medium.com โ€บ @atamhankar22 โ€บ copying-and-processing-arrays-in-python-52bb1530f076
Copying and Processing Arrays in Python | by Amol Tamhankar | Medium
October 29, 2025 - Now, both arrays are independent โ€” modifying arr2 doesnโ€™t affect arr1. ... However, shallow copies can become tricky when dealing with nested lists. ... Why did this happen? Because the .copy() method only copied the outer list โ€” the inner lists are still shared between arr1 and arr2. To solve this, Python provides the deep copy feature via the copy module.
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Aims
python.aims.ac.za โ€บ pages โ€บ cp_mutable_objs.html
21. Be careful: copying arrays, lists (and more) โ€” AIMS Python 0.7 documentation
Our (possible) perception: First we create an array A and assign it values; so somewhere in memory are those 5 values, and that vector-like thing of them is A. If we type A, Python gets all the array values into memory and prepares to work with them. And B = A means: get the full set of values in A, put them somewhere currently unused in memory, and store that new array under the name B. After this, A and B are separate arrays, so we have the same values in two separate locations---copy complete!
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w3resource
w3resource.com โ€บ numpy โ€บ array-creation โ€บ copy.php
NumPy: numpy.copy() function - w3resource
Initially, an array 'a' is created with values [2, 3, 4]. Then, a reference to 'a' is assigned to 'b', and a copy of 'a' is created using np.copy() and assigned to 'c'. When we change the value of the first element of 'a' to 15, it reflects in 'b' as well because 'b' is just a reference to the same memory location as 'a'. So, 'b' also contains [15, 3, 4]. However, the copy 'c' is unaffected by the change in 'a' because it is a deep copy and has its own separate memory location.
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NumPy
numpy.org โ€บ doc โ€บ 2.0 โ€บ reference โ€บ generated โ€บ numpy.ndarray.copy.html
numpy.ndarray.copy โ€” NumPy v2.0 Manual
>>> import copy >>> a = np.array([1, 'm', [2, 3, 4]], dtype=object) >>> c = copy.deepcopy(a) >>> c[2][0] = 10 >>> c array([1, 'm', list([10, 3, 4])], dtype=object) >>> a array([1, 'm', list([2, 3, 4])], dtype=object)