Python Examples

Python Program to Print all Prime Numbers in an Interval

python prime number is a number that has no factor other than 1 and the number itself. Some prime numbers are 2,3,5,7,11,13, and so on. Numbers like 8 are not prime but composite numbers (4×2).

How do you Find Prime Numbers in Python?

Prime numbers in Python can be derived with the help of the for loop. The prime numbers are derived by using sum pre-defined functions mentioned in the SumPy module.

Source Code for finding the python prime number between a specified interval

In the program given below, we have specified two variables lwr, and upr. Lwr is used to store the lower interval, and the upr variable stores the upper interval.

                    

lwr = 900

upr = 1000

print("Prime numbers between", lwr, "and", upr, "are:")

for numb in range(lwr, upr + 1):

# all prime numbers are greater than 1

if numb > 1:

for a in range(2, numb):

if (numb % a) == 0:

break

else:

print(numb)

Output

                    

Prime numbers between 900 and 1000 are:

907

911

919

929

937

941

947

953

967

971

977

983

991

997

Is Prime Number Function Python?

In the Python programming language, some library functions can derive prime numbers. The SymPy is a python module that consists of the library functions. These are listed below:

  1. isprime(n): This function tests whether a given number ‘n’ is prime or not.
  2. primerange(a, b): The prime range function generates the list of all the prime numbers within the specified range a and b.
  3. randprime(a, b): This function returns a random prime number within the specified range.
  4. primepi(n): This function returns the count of the prime numbers less than or equal to n.
  5. prime(nth): The nth prime is returned by using this function, with primes indexed as prime(1) = 2. The nth prime is n*log(n) and cannot exceed 2**n.
  6. prevprime(n): The prevprime function is used to return the previous prime function that is lesser than n.
  7. nextprime(n): This function returns the next prime number greater than n.
  8. sieve.primerange(a, b): It’s a dynamically evolving Eratosthenes sieve that generates all prime integers in the range [a, b].

How do you Find the Prime Numbers from 1 to 100 in Python?

python prime number

Source

To find the prime numbers between 1 to 100 we first use a for loop for iterating a loop between 1 and 100. Within this for loop, we iterate another for loop to check whether the number is divisible or not. If the number is not divisible, we increment the counter, and a break statement is used to skip that number.

                    

for Numb in range (1, 101):

cnt = 0

for a in range(2, (Numb//2 + 1)):

if(Numb % a == 0):

cnt = cnt + 1

break

if (cnt == 0 and Numb != 1):

print(" %d" %Numb, end = ' ')

Output:

                    

2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

What is the Logic of Prime Number in Python?

A prime number is a positive number N that is greater than 1. A prime number does not have any positive divisors other than one and the number itself.

Few prime numbers include 2, 3, 5, 7, 11, and so on. The logic behind finding out whether or not a number is prime is to iterate that number from 2 to N/2 using a for loop and check if that number. If any number divides then it is not a prime number if it does, it is a prime number.

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