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Python Program to Find Prime Numbers in Range

Welcome to this captivating tutorial on Python program to print all prime numbers in a given range or interval!

Prime numbers hold a special place in mathematics and have intrigued mathematicians and number enthusiasts for centuries. These unique numbers possess an inherent beauty and are divisible only by 1 and themselves, leaving no room for any other divisors in between.

Examples of prime numbers include 2, 3, 5, 7, 11, and so on.

But why should we care about prime numbers in real life? The concept of prime numbers finds application in various domains, ranging from cryptography to number theory and algorithm design.

They are the fundamental building blocks behind encryption algorithms that safeguard our digital communication, ensuring secure transactions and confidential information exchange.

Consider online shopping, where prime numbers play a crucial role in secure communication protocols, keeping your credit card information safe from prying eyes. Additionally, prime numbers find application in fields such as computer science, data analysis, and prime factorization algorithms.

Here, we will write a Python program to find prime numbers in range. We'll explore various techniques, including optimized algorithms and practical coding examples, to efficiently generate and validate prime numbers.

You will also use prime number program in Python to print 1 to 100. So, let’s get started!

Python Program to Find Prime Numbers in Range

Code

# Print all prime numbers in a given range in Python

def is_prime(n):
    if n < 2:
        return False
    for i in range(2, int(n**0.5) + 1):
        if n % i == 0:
            return False
    return True

# Taking input from the user
start = int(input("Enter the starting number of the range: "))
end = int(input("Enter the ending number of the range: "))

# Printing prime numbers within the range
print("Prime numbers between", start, "and", end, "are:")
for num in range(start, end+1):
    if is_prime(num):
        print(num)

Output

Enter the starting number of the range: 1
Enter the ending number of the range: 50
Prime numbers between 1 and 50 are:
2
3
5
7
11
13
17
19
23
29
31
37
41
43
47

Explanation

We used the is_prime function that takes a number n as input and determines if it is a prime number. The function first checks if n is less than 2 because prime numbers are defined as greater than 1.
Then, using a for loop, it iterates from 2 to the square root of n (converted to an integer plus 1). Within each iteration, it checks if n is divisible by the current value of i.
If it is divisible, n is not a prime number and the function returns False. If no divisors are found, the function returns True, indicating that n is a prime number.
We then take input from the user to specify the starting and ending numbers of the range within which we want to find the prime numbers.
Next, we use a for loop to iterate through each number within the given range. For each number, we call the is_prime function to check if it is prime. If it is, we print the number.

Python Course

Print Prime Numbers from 1 to 100 in Python

Code

# Prime number program in Python to print 1 to 100

def is_prime(n):
    if n < 2:
        return False
    for i in range(2, int(n**0.5) + 1):
        if n % i == 0:
            return False
    return True

# Printing prime numbers from 1 to 100
print("Prime numbers from 1 to 100 are:")
for num in range(1, 101):
    if is_prime(num):
        print(num)

Output

Prime numbers from 1 to 100 are:
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

Explanation

In this program, we define a function called is_prime that takes a number n as input and determines if it is a prime number. The function follows the same logic as explained in the previous example.

We then use a for loop to iterate through each number from 1 to 100. For each number, we call the is_prime function to check if it is prime. If it is, we print the number.

By running this program, you will see all the prime numbers from 1 to 100 being printed.

Print First n Prime Numbers in Python

Code

# Python program to print first n prime numbers

def is_prime(num):
    if num < 2:
        return False
    for i in range(2, int(num**0.5) + 1):
        if num % i == 0:
            return False
    return True

# Taking input from the user
n = int(input("Enter the value of n: "))

# Printing the first n prime numbers
count = 0
num = 2
print("The first", n, "prime numbers are:")
while count < n:
    if is_prime(num):
        print(num)
        count += 1
    num += 1

Output

Enter the value of n: 10
The first 10 prime numbers are:
2
3
5
7
11
13
17
19
23
29

Explanation

Here, we defined the is_prime function that takes a number num as input and checks if it is a prime number. The function follows the same logic as in the previous examples.
We take input from the user to specify the value of n, which represents the number of prime numbers to be printed.
Using a while loop, we keep track of the count of prime numbers found (count) and iterate through numbers starting from 2 (num). Inside the loop, if num is prime, we print it, increment the count, and proceed to the next number. We continue this process until we find first n prime numbers.

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