The best way to solidify concepts is to practice. These exercises cover functions, loops, and conditionals using a classic problem: finding prime numbers in a range.

Running the program

Save the code in a file named primes.py and run it from the terminal with:

python primes.py

Function to check if a number is prime

A number is prime if it’s only divisible by 1 and itself. The function iterates through possible divisors:

def es_primo(num):
    if num == 1:
        return False
    for i in range(2, num):
        if num % i == 0:
            return False
    return True

Loop to find primes in a range

We use a for loop with range(inicio, final + 1) to iterate over all numbers:

def busca_numeros_primos(num_inicio, num_final):
    for num in range(num_inicio, num_final + 1):
        if es_primo(num):
            print(num)
            total_numeros_primos += 1

Measuring execution time

The timeit module lets you measure how long the program takes:

import timeit
inicio_tiempo = timeit.default_timer()
# ... code to measure ...
fin_tiempo = timeit.default_timer()
print(fin_tiempo - inicio_tiempo, "seconds")

Threading version

To speed things up, we can split the range into two halves and process them in parallel with threading.Thread:

num_mitad = int(((num_final - num_inicio) / 2) + num_inicio)
hilo = threading.Thread(target=consulta_primos, args=(num_inicio, num_mitad))
hilo.start()
hilo.join()