Object Value vs Object Type vs Object Id in Python

Objects in Python

Objects are Python’s abstraction for data. All data in a Python program is represented by objects or by relations between objects.

Every object has

  • identity
  • type
  • value.

Topics covered in this story

Image for post

Photo by Author


Object Id vs Object Type vs Object value

Image for post

Photo by Author

a=5
print (type(5))#Output:<class 'int'>
print (id(a))#Output:1613096944

b="hello"
print (type(b))#Output:<class 'str'>
print (id(b))#Output:53076544

Object Identity

An object’s identity never changes once it has been created. You may think of it as the object’s address in memory.

id() function

Syntax: id(object)

  • Returns the **identity **of an object.
  • It is an integer that is unique and constant for this object during its lifetime.
  • Two objects with non-overlapping lifetimes may have the same** id()** value.
  • CPython implementation detail: This is the address of the object in memory.

Example: Let’s find the id of python data types strings, list, tuple, dictionary.

a=5
print (id(a))#Output:1441654768

l=[1,2,3]
print (id(l))#Output:12597256

t=(1,2,3)
print (id(t))#Output:44739208

d={'a':1,'b':2}
print (id(d))#Output:12532704

s="python"
print (id(s))#Output:45025152

How to do identity comparisons:

**is operator**

The is operator is used to compare the identity of two objects.

x is y is True if and only if x and y are the same objects.

id(x)==id(y) is True if and only x and y are the same object.

Example:

x=5
y=5
print (x is y)#Output:True
print (id(x)==id(y))#Output:True
print (id(x))#Output:1441654768
print (id(y))#Output:1441654768

Pictorial Representation

Image for post

Immutable data types:

For immutable datatype, operations that compute new values may actually return a reference to any existing object with the same type and value.

Ex. a = 1; b = 1a and b may or may not refer to the same object with the value one, depending on the implementation

Mutable data types:

For mutable data types, this is not allowed.

c = []; d = []c and d are guaranteed to refer to two different, unique, newly created empty lists.

Example:

c=[1,2]
d=[1,2]
print (c is d)#Output:False
print (id(c))#Output:16857096
print (id(d))#Output:47485256

print (id(c[0]))#Output:1441654704
print (id(c[1]))#Output:1441654720
print (id(d[0]))#Output:1441654704
print (id(d[1]))#Output:1441654720

Pictorial Representation

Image for post

Photo by Author

Containers are some objects which contain references to other objects. Examples of containers are tuples, lists, and dictionaries. The references are part of a container’s value.

List contains only references to objects. Since the list is a** mutable object**, two lists will not have the same id even if the elements are the same.

#devops #python3 #python #data-science #python-programming

What is GEEK

Buddha Community

Object Value vs Object Type vs Object Id in Python
Arvel  Parker

Arvel Parker

1591611780

How to Find Ulimit For user on Linux

How can I find the correct ulimit values for a user account or process on Linux systems?

For proper operation, we must ensure that the correct ulimit values set after installing various software. The Linux system provides means of restricting the number of resources that can be used. Limits set for each Linux user account. However, system limits are applied separately to each process that is running for that user too. For example, if certain thresholds are too low, the system might not be able to server web pages using Nginx/Apache or PHP/Python app. System resource limits viewed or set with the NA command. Let us see how to use the ulimit that provides control over the resources available to the shell and processes.

#[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object]

MEAN Stack Tutorial MongoDB ExpressJS AngularJS NodeJS

We are going to build a full stack Todo App using the MEAN (MongoDB, ExpressJS, AngularJS and NodeJS). This is the last part of three-post series tutorial.

MEAN Stack tutorial series:

AngularJS tutorial for beginners (Part I)
Creating RESTful APIs with NodeJS and MongoDB Tutorial (Part II)
MEAN Stack Tutorial: MongoDB, ExpressJS, AngularJS and NodeJS (Part III) 👈 you are here
Before completing the app, let’s cover some background about the this stack. If you rather jump to the hands-on part click here to get started.

#[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object]

CentOS Linux 8.2 Released and Here is How to Upgrade it

CentOS Linux 8.2 (2004) released. It is a Linux distribution derived from RHEL (Red Hat Enterprise Linux) 8.2 source code. CentOS was created when Red Hat stopped providing RHEL free. CentOS 8.2 gives complete control of its open-source software packages and is fully customized for research needs or for running a high-performance website without the need for license fees. Let us see what’s new in CentOS 8.2 (2004) and how to upgrade existing CentOS 8.1.1199 server to 8.2.2004 using the command line.

#[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object]

systemctl List All Failed Units/Services on Linux

Is there is a command to print list all failed units or services when using systemd on Linux? Can you tell me the systemctl command to list all failed services on Linux?

This quick tutorial explains how to find/list all failed systemd services/units on Linux operating systems using the systemctl command.

#[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object]

Creating RESTful APIs with NodeJS and MongoDB Tutorial

Welcome to this tutorial about RESTful API using Node.js (Express.js) and MongoDB (mongoose)! We are going to learn how to install and use each component individually and then proceed to create a RESTful API.

MEAN Stack tutorial series:

AngularJS tutorial for beginners (Part I)
Creating RESTful APIs with NodeJS and MongoDB Tutorial (Part II) 👈 you are here
MEAN Stack Tutorial: MongoDB, ExpressJS, AngularJS and NodeJS (Part III)

#[object object] #[object object] #[object object] #[object object] #[object object] #[object object] #[object object]