This means that you'll rarely be dealing with raw numbers when it comes to for loops in Python - great for just about anyone! You can define your own iterables by creating an object with next() and iter() methods. Having an iterable method basically means that the data can be presented in list form, where there are multiple values in an orderly fashion. Even strings, despite not having an iterable method - but we'll not get on to that here. Basically, any object with an iterable method can be used in a for loop. In Python this is controlled instead by generating the appropriate sequence. Many languages have conditions in the syntax of their for loop, such as a relational expression to determine if the loop is done, and an increment expression to determine the next loop value.

If you've done any programming before, you have undoubtedly come across a for loop or an equivalent to it. You could use a for loop with a huge number in order to gain the same effect as a while loop, but what's the point of doing that when you have a construct that already exists? As the old saying goes, 'why try to reinvent the wheel?'. The for loop runs for a fixed amount - in this case, 3, while the while loop runs until the loop condition changes in this example, the condition is the boolean True which will never change, so it could theoretically run forever. Print('To infinity and beyond! We're getting close, on %d now!' % (x))Īs you can see, these loop constructs serve different purposes. While loop from 1 to infinity, therefore running forever. For example:įor loop from 0 to 2, therefore running 3 times. Contrast the for statement with the ''while'' loop, used when a condition needs to be checked each iteration, or to repeat a block of code forever. The Python for statement iterates over the members of a sequence in order, executing the block each time. For loops are traditionally used when you have a block of code which you want to repeat a fixed number of times.

What does f loops mean