What are the python variables, declaration, Types, and Scope

Generally, the variables are considered as reserved memory locations to store up different values. In simple words, it means that when a programmer creates a variable, they reserve or put aside some space in the memory. According to the data type of a variable, the interpreter or translator usually allocates or distributes the memory, and they also decide what can be stored in reserved memory. If you are related to the programming field, then we can safely assume that you must be familiar with the concepts of python variables.

But still, most of the people seem confused about the python variable declaration. If you are also confused about it, then you don’t worry as you are not the one-and-only, thousands of people confused about it. Here we are going to discuss everything about python-variables, declaration, Types, and Scope in detail.

What exactly is a Variable in Python?

The python variables are reserved memory locations to Collect or store up different types of values. In simple words, the variables in the python programs provide data to the system or computer for processing.

Usually, each value in Python has a different type of data. In simple words, we can say that Python has various data types. Typically Python has 5 standard types of data that are List, Strings, Numbers, Tuple, and Dictionary, etc.. The python variable may be pronounced by any name or even by alphabets such as aa, a, ABC, etc..

How to create python variables?

The variables are usually considered as containers for storing different data values. Python is different from other types of programming languages, as python doesn’t have any command for declaring or announcing a variable. Any variable generally designed or created the moment the programmer first assigns a value to it. 

Example

x = 5

y = “John”

print(x)

print(y)

It is noteworthy here that the variables don’t require to be declared or pronounced with any specific type and may even change type after variables have been set.

Example

x = 4 # x is of type int

x = “Sally” # x is now of type str

print(x)

It is also considerable that string python variables may be declared either by using single-quote marks or double-quote marks. 

Example

x = “John”

# is the same as

x = ‘John.’

Concatenate Python Variables-:

Now let us check if we can concatenate the different types of data like string and number together. In order to do so, we will take an example. Here we will try to concatenate “Guru” with the number “99”.

No doubt in it that java can concatenate numbers with string without even declaring number as a string. Python is opposite from java since python always needs declaring the numbers as a string first, or else, python may show a type error..

If we try to concatenate “Guru” with the number “99” then we will get the undefined or inexact output-:

a=”Guru”

b = 99

print a+b

But one the integer data is declared or pronounced as string data, then it may concatenate both “Guru” + str(“99”)= “Guru99” in the output. And thus we get the actual output or result-:

a=”Guru”

b = 99

print(a+str(b))

Variable Names-:

There is no doubt in it that usually, a variable may have a very short or small name such as “X and Y” or a more narrative or  descriptive name such as “car name, age, total_volume.” Here we have mentioned the significant rules for python variables-:

  • The name of a python variable should start with an underscore character or letter.
  • Python variable can’t start with any number.
  • Variable may only include underscores and Alpha-numeric characters. For example: (A-z, 0-9, and _ )
  • The python variable names are usually case-sensitive(Age, age, and AGE are three different python variables).

Example

#Legal variable names:

myvar = “John”

my_var = “John”

_my_var = “John”

myVar = “John”

MYVAR = “John”

myvar2 = “John”

#Illegal variable names:

2myvar = “John.”

my-var = “John”

my var = “John.”

Local & Global Python Variables-:

If you are working in python, and you require to utilize the same python variable for the rest of the module or program, then you will declare it as the global variable. On the other hand, if you require to utilize the variable in a particular method or function, then you will declare it as a local variable.

Overview of Python variable declaration-:

Commonly variables of python don’t need a definitive declaration to reserve the memory space. While we assign or give any value to the variable, then the declaration happens automatically. The sign of equal (=)  mainly used to assign the values to the variable.

Basic Data Types in Python-:

Here we have mentioned the standard types of data that included in python-:

  • Python Integers
  • Floating-Point Numbers
  • Python Complex Numbers
  • Python Strings
  • Escape Sequences in Strings
  • Python Raw Strings
  • Python Triple-Quoted Strings

What is Python Variable Scope?

The scope of the python variable is considered that part of the code where it is visible. Actually, you don’t need to use any type of prefixes then for reference to it. Here we are going to discuss the python variable scope.

Types of Python Variable Scope-:

Usually, there are 4 types of variable scope in python, so here we are going to discuss all one by one-:

1. Local scope-:

The local scope in the code body or block of the python lambda or function expression. The local scope of python mainly contains the names that you define inside the function.

2. Enclosing scope-:

Enclosing scope contains the names that you define in the enclosing functions of python. In the enclosing scope, the names are mainly visible from the code of the enclosing and inner functions.

3. Global scope-:

Global scope is topmost scope in the python program, modules, or script. The global scope of python mainly contains all the names that we define at the top level of a module or program. The names included in this python scope are usually visible from everywhere in your code.

4. Built-in scope-:

The built in scope is mainly one of the special python scopes that are loaded or created when we run an open or script an interactive session. This python scope contains mostly names such as the exceptions, and functions attribute that is mainly built into python.

Conclusion-:

We have mentioned all the detailed information about python variables that you should know. We have also mentioned the brief details on the python-variables, declaration, Types, and Scope. Thus, we hope that our blog will become very helpful for you and will clear all your doubts regarding it. Still, if you have any confusion relating to it, then don’t feel any hesitation in contacting us anytime at the Australian assignment. We have a team of experts who are all well qualified, and all have years of experience working in the writing field.

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