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uh hello guys uh welcome to this video
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so in this video i will show you a
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python script which will actually find
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out prime numbers which are between a
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starting and ending range so this is a
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simple python program which is actually
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asked inside competitive exams or
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interview questions as well so how to
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find out prime numbers in a given range
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so this is actually a python program
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that i written right here if i visualize
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the execution right here so i will show
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you step by step how this program is
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executing so first of all we are taking
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input from the user using this uh input
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function so here we'll be accepting the
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start range and the end range so here as
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you can see we need to provide the
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starting range so let's suppose i want
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to find out all the prime numbers
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starting with two and up till 30 so we
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will find out all these prime numbers
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between 2 and 30 so this is my starting
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range and this is my end range so this
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is basically this is your start variable
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two and end variable is 30 so these are
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two global variables and now we are
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simply printing out the prime numbers
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between start and end so as you can see
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so now we come to this for loop and for
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this specific purpose we are using this
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simple for loop inside python so we are
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starting it from the start variable to
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end so we are looping through 2 up till
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31 so 31 is not included as you can see
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n + 1 is not included so we are looping
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through 2 up till
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30 and now inside this for loop the very
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first thing we are checking right here
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that the number must be greater than one
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because as you all know one is not a
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prime number so now in the next line
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here we are comparing that the number
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must be greater than one so in this case
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2 is greater than one so in this
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case the condition will be evalued to
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true and now inside this inner for loop
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here for i in range 2 now again we are
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having this again for loop so we are
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looping through two up till the actual
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number so in this case the number is two
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so the condition will evaluate to true
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and we will be coming under this for
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loop so the condition will be false
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because the number the 2 2 so two is not
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included so so this for loop will end
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and it will print out the actual number
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right here so two will be the prime
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number as you can see the prime numbers
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are those numbers which are div
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divisible by itself and two so it must
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be at least two numbers so two is
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actually a prime number it is divisible
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by itself and also it is divisible by
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two as well so it's a even prime number
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and now we come to the next number which
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is three 3 is greater than
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1 so then we run this inner for loop to
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actually check that if it is divisible
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by two or not so here we simply check
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that three is not divisible by two
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so this condition will evaluate to false
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here
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so now we will check for the uh we will
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iterate through now the i value will
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become three so it will end and again
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three will be printed out three is also
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a prime number so now we come to the
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next iteration which is four four is
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also greater than one so it will come
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into this inner for loop again we will
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be running this inner for loop so now
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we'll be comparing if four is divisible
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by two which in this case is true four
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is not a prime number it's a even number
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so this condition will evolutes to true
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and now the loop will break and now the
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condition will break and as you can see
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it this four number will not be printed
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out and the control will shift to the
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next number which is uh five so now as
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you can see the num value is five here
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four is not a prime number so it is not
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printed out now again five is again
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greater than one so it will come into
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this inner for loop and again we will
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check here five is not divisible by two
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it will break then the i value will be
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three five is also not divisible by
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three so this will again go to the next
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number which is four five is also not
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divisible by
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four and now it will go to the next so
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as soon as i become five the for loop
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will break and then five will be printed
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out so as you can see the control has
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shifted to the else condition so here we
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are printing so it's a very simple
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program guys as you can see how it is
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simple is it is 2 3 5 so in this
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case now six with six is not a prime
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number so it will come into this for
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loop six is divisible by two so now the
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loop will break and now it will move to
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the next number which is seven so again
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seven will be looping through so this is
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a very simple logic that we have written
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inside this so we are simply having the
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inner the outside for loop is for
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checking that the number must be greater
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than one and in the inner for loop we
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are
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checking for the divisibility if it's
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not an even number so we are checking
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that it should not be divisible by any
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even number so seven as you can see it's
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not divisible by two neither it's three
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four so it will run
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until 7 so as soon as it reaches seven
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the uh loop will break so you can just
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see the flow guys the program flow 2 3 5
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7 so now we have it will loop through
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all the time so eight the loop will
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break now it will go to the ninth so
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just you can see the flow here let me
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just uh do the you can
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see the flow of the
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program it will run up till 30
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number so as you can see in this way the
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program will run and it will print out
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all the prime numbers which are residing
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between two and 30 so you can see the uh
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control flow of the program
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so it will
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reach it will loop through all the
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numbers which are
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there so as you can see it
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is you can pause the video and write
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this program guys it's a very simple
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logic once you understand it keep
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watching this video you will understand
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how it is executing it it is using for
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loop here and inside
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this so you can
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see that's all so it printed out all the
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prime numbers which are residing between
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2 and
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30
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so this is your outer for loop which is
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looping
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through the number starting and ending
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inside this we have if condition then
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inside inner loop we are checking for
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the divisibility of
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two if it is divisible by two then we
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are breaking it if it is not then we are
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printing the number so in this way you
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can check out and then you can paste
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this program inside visual studio as
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well and run this program as well so if
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i run this program here also you will
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see it will ask for
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the starting range let me provide two
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and 10 so it will print out all the
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prime numbers so you can run it in vs
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code as well just pasting this program
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right here very simple program and thank
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you very much for watching this video
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and also check out my website
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freemediattools.com
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uh which contains thousands of tools
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