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Python variables and constraints, we shall start with our discussion with Python variables.

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We know that in any programming language we define some variables.

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So variables are nothing but some named memory locations.

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So how many memory locations will be defined under one variable that will be decided by its dictate?

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That is a side of that data.

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So here we are having the python variables.

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So in Python Biddable is a name name.

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The location used to store data in the memory.

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Each variable must have a unique name called identified.

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So depending upon the data type of the variable, the number of bytes going to be occupied, that will

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be decided and the memory address of that memory block will be having a name which is accessible from

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the programming code.

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So that will make the programmers it will make the programmers easier to write their goals in Python.

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Variables do not need declension to resolve memory space.

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The variable declension or the variable initialization happens automatically when we assign available

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assign a value to a variable.

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So there is no need to define all the variables at the beginning of the code, like in our C C++, we

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always write all the variables and the respective negatives at the beginning of our code and then only

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we can use them in the respective successive codes.

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But that constraint is not there in Python.

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That variable declaration and the variable initialization can be done in the same statement.

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So here you see this account is equal to one hundred.

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The underscore name is Robyn and say H1, H2 is three is equal to 44, comma 37, comma 22.

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So in this way, you see at this particular line, the variable age one is two, three, they are defined.

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Their respective vegetables have got initialised and here you see here we put the integer value so the

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we will have their respective little type integer in that case.

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So in this way, we can have multiple variables, can be initialized, can be can be declared in the

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same statement.

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And there is a syntax in which we are right.

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So there is no need to put the semicolon at the end of the Python statement.

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So that's why no semicolon is there.

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So that's why this is a way to define and also to initialize variables.

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He constantly is a type of vegetable whose value cannot be changed, and it is helpful to think of Constance

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as containers that hold information which cannot be changed later on.

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So that's why the constant is not but available, which will be holding a value.

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But the value cannot be changed later on.

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So naming conventions for variables and constants in Biocon.

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So that is that nomenclature should be purposeful.

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We all know that it is a good program aspect is the best practices of the developers and programmers.

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Is that the variable name, the function name, the class name should be purposeful hamdard very variable

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name.

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I should get the idea what is the purpose of the variable and what kind of value it is supposed to hold

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that use name.

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There is a camel case notation.

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What is the meaning of this since the first letter will be in the lowercase.

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But the next two words.

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If there are multiple words in the variable name, they'll be starting with the capital letters and

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the rest of the letters will be in the lowercase.

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So use capital letters to the present are constant symbols like you're at the root of hash.

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Exclamation dollard percentage should not be used.

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Don't start with the digit that is very common in the previous video.

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Also, we are showing you that one one variable is not a valid variable name, but variable one is a

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valid variable name.

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So constants are put into function models and meant to be meant not to be changed to I.

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As I discussed earlier, though, constants cannot be changed later on.

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So constant and variable names should have the combination of letters in lowercase that is small a too

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small Z or uppercase letters that is a capital A to capital Z are digits that is to nine or an underscore.

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These are the valid characters in naming.

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So let us go for further discussion with some demonstration for easier understanding in decision.

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We are discussing and demonstrating how to define constants and variables so constants in Python can

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be defined.

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It is a common practice to write all the constraint, the constant name, all in the capital letters.

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So physical two three point four gravity is equal to nine point eight.

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In this way, the constants can be defined in our python.

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And now we are going to define that.

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How that variables can be defined and how to declare variable, how to assign valid values on them so

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is equal to Apple.

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So now it is available as the apple is up to type text or string.

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So it be up to type string here.

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So print a so I'll get printed.

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So now let's go for the execution.

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This line has got no print, so.

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That's right.

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No, no outcome is there.

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So let me go for that print.

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If you go for the sprint by we're getting this one and been one for now for this part.

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If I go for the execution, it will come like this.

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So is the apple so pretty, so it is printing Apple here, changing the value of available so that can

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be done using reassignment.

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So easy go to Aeroplan.

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So now if you type this one and then print it, it is printing their respective string.

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So next time I'm printing, I'm just assigning 100 to it.

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So now if we print it, then it is getting the value 100.

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So you're going to find that the same biddable sometimes may be initialized with the string, sometimes

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with the integer, and that is allowed in Python because in case of Python, Python, Python is a dynamic

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type language that means the variables will be decided during the runtime.

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So during the runtime, whatever the value the variable is containing, that will decide the fate of

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them.

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And in case of Python, there is no need to declare the variable separately.

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At the beginning of the code, we can define variable as when we request to use them and he can find

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that here.

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This is Aeroplane's.

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So that means that EA has got the data type string and the next part of the code that will be treated

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as a string until unless it is getting initialized with some other data type.

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So here we ablated is equal to 100.

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So the next part of the code will be treated as the type integer until unless is getting initialized

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with some other type of Pelosse assigning multiple values to be available.

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So B, C, D, all these three variables are getting assigned with this one, 2.5 Penhallow respectively

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in a single single line.

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So this one will be assigned to be 2.5, will be assigned to C and will be assigned to.

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So when you are printing B, C and D, we're getting the outcome as one two point five.

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And hello.

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Next one, is that assigning the same value to multiple variables, using a same statement in the same

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line, you know, so B is able to see is the D is equal to fight.

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That was if I was getting assigned to B, C and D, but at the same time in a single segment, single

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assignment STATMAN.

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So Phi Phi Phi is going to get printed here.

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So in this example and demonstration, we have discussed that how to define constants and how to define

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variables and how to assign values on them.

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Thanks for watching this video.