Python - Print All Prime Numbers In Any Interval

in this video I show you how to create a function that prints out all prime numbers in any given interval

[wrttech]

l = int(input("low bound: "))
u = int(input("upper bound: "))

for num in range(l, u+1):
if num > 1:
for i in range(2, num):
if num % i == 0:
break
else:
print(num)

[naveenkumarg]

As a beginner in coding that else statement outside for loop felt genius

[brendanthorne]

Does the second for loop "for i in range(2, num):" never check the number itself so that we can break out of the loop? Example num =100 will only ever check up to 99. So that the for loop is never satisfied?

[houseofelectronics]

Great tutorial. Just a suggestion below
Instead of "for i in range(2, num)",
"for i in range(2, (num//2 + 1))" would have better time complexity isn't it? Because for any i which is greater than num/2, num won't divide by i

[snehap]

If finding prime number between 2 and 200, Does this function work? Because 2 divided by 2 will break and will not print 2, but 2 is a prime number.

[telsaabi]

How can we modify this so that given a positive integer x, it computes the fraction
f(x) of prime numbers less than or equal to x, i.e., f(x) = y/x, where y is the the number of prime
numbers less than or equal to x

[cokfarm]

how to write this code for, prime numbers between 100 & 200, and output as 5 numbers in 1 line and then next line, a little tricky question...

[dsvuuyq]

wonderful, i really appreciate that. Yet i am wondering why the else can go outside the for loop but not on the same vertical line with 'if'. What does it mean sir, hope you can answer me~~

[jadeboom]

sir can you write it without using a break command

[driesdep]

Just curious: why didn't you create a function?

[ayearninghope]

If we know 2 isn't a factor of n, wouldn't it be better to avoid running this code over rest of the even numbers in our integer range (since even numbers are all factors of 2)?

[bharadhwajsinguluri]

how to print only first prime number in this condition. i.e output must be only single number

[chadvukondiifirstuu]

How to get all that output in single line

[bhavanipullepu]

When i was doing this in the range between 1 to is not including in the list when the output was dont know why it was not including....pls give me the solution sir

[FC]

In pydroid it doesnt work but in pycharm it works i must have a stupid IDE

[bryceberry]

For some reason, I copied this exactly into IDLE and it is only printing "2". Nothing else