How to make a NumPy array read-only? Last Updated : 04 Nov, 2022 Comments Improve Suggest changes Like Article Like Report Let's discuss how to make NumPy array immutable i.e that can not be rewritten or can't be changed. This can be done by setting a writable flag of the NumPy array to false. Syntax: array.flags.writable=False This set the writable flag to false and hence array becomes immutable i.e read-only. See the example below Example: Python import numpy as np a = np.zeros(11) print("Before any change ") print(a) a[1] = 2 print("Before after first change ") print(a) a.setflags(write=False) print("After making array immutable on attempting second change ") a[1] = 7 Output: Before any change [0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.] Before after first change [0. 2. 0. 0. 0. 0. 0. 0. 0. 0. 0.] After making array immutable on attempting second change Traceback (most recent call last): File "gfg9.py", line 11, in <module> a[1]=7 ValueError: assignment destination is read-only Comment More info S shivanshsaxena1 Follow Improve Article Tags : Python Python-numpy Python numpy-arrayManipulation Explore Python FundamentalsPython Introduction 3 min read Input and Output in Python 4 min read Python Variables 5 min read Python Operators 5 min read Python Keywords 2 min read Python Data Types 8 min read Conditional Statements in Python 3 min read Loops in Python - For, While and Nested Loops 7 min read Python Functions 5 min read Recursion in Python 6 min read Python Lambda Functions 5 min read Python Data StructuresPython String 5 min read Python Lists 5 min read Python Tuples 4 min read Python Dictionary 3 min read Python Sets 6 min read Python Arrays 7 min read List Comprehension in Python 4 min read Advanced PythonPython OOP Concepts 11 min read Python Exception Handling 5 min read File Handling in Python 4 min read Python Database Tutorial 4 min read Python MongoDB Tutorial 2 min read Python MySQL 9 min read Python Packages 12 min read Python Modules 7 min read Python DSA Libraries 15 min read List of Python GUI Library and Packages 3 min read Data Science with PythonNumPy Tutorial - Python Library 3 min read Pandas Tutorial 6 min read Matplotlib Tutorial 5 min read Python Seaborn Tutorial 15+ min read StatsModel Library- Tutorial 4 min read Learning Model Building in Scikit-learn 8 min read TensorFlow Tutorial 2 min read PyTorch Tutorial 7 min read Web Development with PythonFlask Tutorial 8 min read Django Tutorial | Learn Django Framework 7 min read Django ORM - Inserting, Updating & Deleting Data 4 min read Templating With Jinja2 in Flask 6 min read Django Templates 7 min read Python | Build a REST API using Flask 3 min read How to Create a basic API using Django Rest Framework ? 4 min read Python PracticePython Quiz 3 min read Python Coding Practice 1 min read Python Interview Questions and Answers 15+ min read Like