- How to learn Ethical Hacking?
- How to become a Ethical Hacker ? Know about the requirements to become one
- Introduction to Cyber Security | A Complete Guide
- Top Reasons to Learn Cyber Security | Everything You Need to Know to Become an Expert
- CyberSecurity Framework | How to Implement | A Definitive Guide with Best Practices [ OverView ]
- The Impact of AI and Machine Learning on Cybersecurity | Everything You Need to Know
- What is Certified Ethical Hacker (CEH) Certification and Why is it Important? [ OverView ]
- Benefits Of ECSA Certification | Everything You Need to Know | Expert’s Top Picks
- Top Most OSINT Tools – Open Source Intelligence | Expert’s Top Picks
- Cyber Security Salary in India : Everything You Need to Know
- What is Computer Security? Free Guide Tutorial & REAL-TIME Examples
- Ethical Hacker Salary and Job Description | Everything You Need to Know
- Hacking Tools and Software | All you need to know [ OverView ]
- What is DES? Free Guide Tutorial & REAL-TIME Examples
- How to Become an Ethical Hacker?
- Which are the Best Network Security Certifications?
- Cybersecurity Consultant Career Path
- The Most Effective Data Encryption Techniques
- Great CISSP Books and Study Guides for the CISSP Certification
- What Is Kerberos?
- Top CISSP Domains
- Cyber Security Career Path
- CISSP Certification Exam Guide 2020
- Top Cyber Security Trends for 2020
- CISSP Exam Online 2020
- Compare and Contrast Physical and Environmental Security Controls
- What is information security architect?
- Certified Information Systems Security Professional (CISSP) Certification
- Top Cyber Security Jobs
- What is CISA Certification?
- What is Threat Modeling?
- Certified Information Security Manager (CISM) Certification
- Information Security Management Principles
- Network Perimeter Security Design
- Things You Must Know About Cyber Security in the Cloud
- What is ECSA?
- Why is Cybersecurity Important?
- Tips to Clear Certified Ethical Hacker (CEH) Exam
- Average Annual Salary of a CISSP Certified Professional
- “How to Become a Cyber Security Engineer? “
- Who is an Ethical Hacker?
- What are the requirements to become Cissp certified?
- The Phases of Ethical Hacking
- What is Ethical Hacking?
- Top Ethical Hacking Certifications
- Hash in Python
- How to learn Ethical Hacking?
- How to become a Ethical Hacker ? Know about the requirements to become one
- Introduction to Cyber Security | A Complete Guide
- Top Reasons to Learn Cyber Security | Everything You Need to Know to Become an Expert
- CyberSecurity Framework | How to Implement | A Definitive Guide with Best Practices [ OverView ]
- The Impact of AI and Machine Learning on Cybersecurity | Everything You Need to Know
- What is Certified Ethical Hacker (CEH) Certification and Why is it Important? [ OverView ]
- Benefits Of ECSA Certification | Everything You Need to Know | Expert’s Top Picks
- Top Most OSINT Tools – Open Source Intelligence | Expert’s Top Picks
- Cyber Security Salary in India : Everything You Need to Know
- What is Computer Security? Free Guide Tutorial & REAL-TIME Examples
- Ethical Hacker Salary and Job Description | Everything You Need to Know
- Hacking Tools and Software | All you need to know [ OverView ]
- What is DES? Free Guide Tutorial & REAL-TIME Examples
- How to Become an Ethical Hacker?
- Which are the Best Network Security Certifications?
- Cybersecurity Consultant Career Path
- The Most Effective Data Encryption Techniques
- Great CISSP Books and Study Guides for the CISSP Certification
- What Is Kerberos?
- Top CISSP Domains
- Cyber Security Career Path
- CISSP Certification Exam Guide 2020
- Top Cyber Security Trends for 2020
- CISSP Exam Online 2020
- Compare and Contrast Physical and Environmental Security Controls
- What is information security architect?
- Certified Information Systems Security Professional (CISSP) Certification
- Top Cyber Security Jobs
- What is CISA Certification?
- What is Threat Modeling?
- Certified Information Security Manager (CISM) Certification
- Information Security Management Principles
- Network Perimeter Security Design
- Things You Must Know About Cyber Security in the Cloud
- What is ECSA?
- Why is Cybersecurity Important?
- Tips to Clear Certified Ethical Hacker (CEH) Exam
- Average Annual Salary of a CISSP Certified Professional
- “How to Become a Cyber Security Engineer? “
- Who is an Ethical Hacker?
- What are the requirements to become Cissp certified?
- The Phases of Ethical Hacking
- What is Ethical Hacking?
- Top Ethical Hacking Certifications
- Hash in Python

Hash in Python
Last updated on 22nd Sep 2020, Artciles, Blog, Cyber Security
Python hash()
- The hash() method returns the hash value of an object if it has one.
- Hash values are just integers that are used to compare dictionary keys during a dictionary lookup quickly.
- Internally, the hash() method calls __hash__() method of an object which is set by default for any object. We’ll look at this later.
What is Python Hash?
- Python is a high-level programming language that comes with a variety of built-in libraries which comprises many functions and modules. Hash in Python is one such module.
- Hash is used to return the hash value of any object. In a programming language, the hash is used to return integer values, which are actually utilized in comparing dictionary keys with the help of the dictionary lookup.
- It calls for _hash_() of an object. While using the hash method the following syntax must be used: hash (object)
Subscribe For Free Demo
Error: Contact form not found.
Hashing
It is a process where the algorithm is used for mapping data to a fixed-length where data can be of any size. This is known as a hash value. It is used to produce high performance and direct access to data structures. This enables the storage of a large amount of data that can be accessed quickly and easily.
hash() Syntax
The syntax of hash() method is:
hash(object)
hash() Parameters
hash() method takes a single parameter:
- object – the object whose hash value is to be returned (integer, string, float)
Return value from hash()
- hash() method returns the hash value of an object if it has one.
- If an object has custom __hash__() method, it truncates the return value to the size of Py_ssize_t.
Examples
1.How hash() works in Python?
# hash for integer unchanged
- print(‘Hash for 181 is:’, hash(181))
# hash for decimal
- print(‘Hash for 181.23 is:’,hash(181.23))
# hash for string
- print(‘Hash for Python is:’, hash(‘Python’))
Output
Hash for 181 is: 181
Hash for 181.23 is: 530343892119126197
Hash for Python is: 2230730083538390373
2. Hash() for an immutable tuple object?
hash() method only works for immutable objects as tuple.
# tuple of vowels
- vowels = (‘a’, ‘e’, ‘i’, ‘o’, ‘u’)
- print(‘The hash is:’, hash(vowels))
Output
The hash is: -695778075465126279
3. How hash() works for custom objects?
As stated above, hash() method internally calls __hash__() method. So, any objects can override __hash__() for custom hash values.
But for correct hash implementation, __hash__() should always return an integer. And, both __eq__() and __hash__() methods have to be implemented.
hash() for Custom Objects by overriding __hash__()
- class Person:
- def __init__(self, age, name):
- self.age = age
- self.name = name
- def __eq__(self, other):
- return self.age == other.age and self.name == other.name
- def __hash__(self):
- print(‘The hash is:’)
- return hash((self.age, self.name))
- person = Person(23, ‘Adam’)
- print(hash(person))
Output
The hash is:
3785419240612877014
Note: You don’t have to implement __eq__() method for the hash as it is created by default for all objects
The above example describes how to override both _eq_() and _hash_() and compare your own custom objects.
You can refer the below table to understand how to implement custom hash values:
_eq_() | _hash_() | Description |
---|---|---|
If mutable objects are defined | Don’t define | Hash key value must be immutable |
If defined by default | Defined by default | All objects will be compared as unequal |
Not defined | Don’t define | In case _eq_() is not defined, then there is no need to define hash as well |
Defined | Not defined | _hash_() will automatically get adjusted to none and TypeError will be raised |
Defined | Do not wish to hash | _hash_= None |
TypeError will be raised | ||
Defined | Retain from Parent | _hash_ = ._hash_ |
Why mutable objects cannot be Hashed?
The restriction on mutable objects actually simplifies the hash table in huge terms. If in case, mutable objects were permitted for hashing, then the hash table must be updated every single time when the value of an object is updated.
In Python, there are only two objects which use hash tables that are dictionaries and sets.
- A dictionary is known as an associative array. Only the keys can be hashed in a dictionary and the values cannot be hashed. Hence, a dictionary key must always be an immutable object and the while values can remain anything.
- A set consists of unique objects that can be hashed. If there are non-hashable objects in a set, you cannot use a set and instead you must consider using a list.