In Python, there are mainly two ways to create loops: the The basic syntax of the In simple terms, for the Let’s examine how the In this example, the initial variable If the condition is always true, the The above code runs indefinitely because of the condition You can also attach an In this code, when Through examples, we will explore some useful ways to use the You can write a program that keeps requesting input from the user until valid input is received.<\/p>\n\n\n\n In this case, the program continues to prompt for input until the user enters a number. If an invalid input is received, it shows an error message.<\/p>\n\n\n\n You can write a program that reads a file line by line and stops when there is no more data to read.<\/p>\n\n\n\n This code opens a file and prints its content while reading each line sequentially. The loop ends when there are no more lines to read.<\/p>\n\n\n\n When using the for<\/code> statement and the while<\/code> statement. In this course, we will learn in detail how the while<\/code> statement works and how to use it. The while<\/code> statement allows the block of code to be executed as long as the given condition is True<\/code>.<\/p>\n\n\n\nBasic Structure of the while Statement<\/h2>\n\n\n\n
while<\/code> statement is as follows:<\/p>\n\n\n\nwhile condition:\n block of code to execute\n (usually includes code that makes the condition false)<\/code><\/pre>\n\n\n\nwhile<\/code> statement, the block of code below is repeatedly executed every time the condition is true. And when the condition becomes false, the loop ends. Now let’s look at a simple example of a while<\/code> statement.<\/p>\n\n\n\nBasic Example<\/h2>\n\n\n\n
while<\/code> statement works through an example. Here, we will look at a simple example that prints the numbers from 1 to 5.<\/p>\n\n\n\ni = 1\nwhile i <= 5:\n print(i)\n i += 1<\/code><\/pre>\n\n\n\ni<\/code> is set to 1. The while<\/code> statement continues executing the loop as long as the condition i <= 5<\/code> is true. Inside the loop, it prints the value of i<\/code> and adds 1 to i<\/code>. Eventually, when i<\/code> becomes 6, the condition evaluates to false, and the loop ends.<\/p>\n\n\n\nInfinite Loop<\/h2>\n\n\n\n
while<\/code> statement can enter an infinite loop. This means that the program will keep running without stopping. Infinite loops can be useful when paired with control mechanisms that appropriately end the loop.<\/p>\n\n\n\nwhile True:\n user_input = input(\"Enter 'q' to exit: \")\n if user_input == 'q':\n break<\/code><\/pre>\n\n\n\nTrue<\/code>, but when the user enters ‘q’, the loop will terminate through the break<\/code> statement.<\/p>\n\n\n\nUsing an else Block with a while Statement<\/h2>\n\n\n\n
else<\/code> block to the while<\/code> statement. The else<\/code> block is executed after the&nbps; while<\/code> block is finished, unless the loop was terminated by a break<\/code> statement.<\/p>\n\n\n\ni = 1\nwhile i <= 5:\n print(i)\n i += 1\nelse:\n print(\"The loop has ended naturally.\")<\/code><\/pre>\n\n\n\ni<\/code> becomes 6, the while<\/code> loop ends, and the statements in the else<\/code> block are executed.<\/p>\n\n\n\nPractical Applications of the while Statement<\/h2>\n\n\n\n
while<\/code> statement. Each example demonstrates how the while<\/code> statement can be used to solve more complex problems.<\/p>\n\n\n\nUser Input Validation<\/h3>\n\n\n\n
while True:\n number_str = input(\"Please enter a number: \")\n try:\n number = int(number_str)\n break\n except ValueError:\n print(\"That's not a valid number. Please try again.\")<\/code><\/pre>\n\n\n\nReading Until End of File<\/h3>\n\n\n\n
with open('some_file.txt', 'r') as file:\n line = file.readline()\n while line:\n print(line, end='')\n line = file.readline()<\/code><\/pre>\n\n\n\nThings to Be Careful About When Using while Statements<\/h2>\n\n\n\n
while<\/code> statement, it is important to set the condition clearly to avoid getting stuck in an infinite loop. Infinite loops can often stop the program and create unintended situations. Therefore, within the loop, you should properly modify the condition or use statements like break<\/code> to ensure the loop ends as intended.<\/p>\n\n\n\n