Sometimes they are necessary and welcomed, but most of the time they are unwanted. Such a loop is called an infinite loop. So now we have a while loop with the statement, while (True), which by nature creates an infinite loop. If you are not careful while writing loops, you will create infinite loops. while expression: statement(s) Here, statement(s) may be a single statement or a block of statements with uniform indent. Once the condition changes to false the loop stops. An infinite loop occurs when a program keeps executing within one loop, never leaving it. Threads: 1. When a while loop is encountered, is first evaluated in Boolean context. Then is checked again, and if still true, the body is executed again. In general, Python control structures can be nested within one another. An infinite loop might be useful in client/server programming where the server needs to run continuously so that client programs can communicate with it as and when required. Take a look at the syntax of while loop in python. To make the condition always true, there are many ways. But that’s not bad since you may not always know the exit condition when you setup the loop or may have multiple exit conditions. You can use break to exit the loop if the item is found, and the else clause can contain code that is meant to be executed if the item isn’t found: Note: The code shown above is useful to illustrate the concept, but you’d actually be very unlikely to search a list that way. Instead of giving True boolean value for the condition, you can also give a condition that always evaluates to True. But in this case I would expect it to use next to nothing. 4.1 and 2. Posts: 2. The example illustrates how the else statement works with the while loop. 3. For certain situations, an infinite loop may be necessary. Python; while loop in Python (infinite loop, etc.) It continues to execute the body of the while loop as long as the condition is true. In this tutorial, we will study the while loop and in the next tutorial, we will study the for loop. stennow on May 11, 2020. So for an infinite loop in python, should I expect that it would use up tons of memory, or does it scale according to what is being done, and where? In programming, there are two types of iteration, indefinite and definite: With indefinite iteration, the number of times the loop is executed isn’t specified explicitly in advance. Programming is like a circus: you gotta keep the lions in the ring. The team members who worked on this tutorial are: Master Real-World Python Skills With Unlimited Access to Real Python. Itertools is a library that creates efficient iterators. The expression in the while statement header on line 2 is n > 0, which is true, so the loop body executes. Definite iteration is covered in the next tutorial in this series. Just remember that you must ensure the loop gets broken out of at some point, so it doesn’t truly become infinite. Another one of the control flow statements is loops. 2.while loop. As you can notice in an example above, there is an if-else condition inside the while … Infinite loops can be very useful. In this case, the loop will run indefinitely until the process is stopped by external intervention (CTRL + C) or when a break statement is found (you will learn more about break in just a moment). When you’re finished, you should have a good grasp of how to use indefinite iteration in Python. Example of an infinite loop: Some of these methods are: Write boolean value true in place of while loop condition. When the body of the loop has finished, program execution returns to the top of the loop at line 2, and the expression is evaluated again. Email, Watch Now This tutorial has a related video course created by the Real Python team. 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