R Programming By Example

While loops

Finally, we will take a look at the while loops which use a different way of looping than for loops. In the case of for loops, we know the number of elements in the object we use to iterate, so we know in advance the number of iterations that will be performed. However, there are times where we don't know this number before we start iterating, and instead, we will iterate based on some condition being true after each iteration. That's when while loops are useful.

The way while loops work is that we specify a condition, just as with if…else conditions, and if the condition is met, then we proceed to iterate. When the iteration is finished, we check the condition again, and if it continues to be true, then we iterate again, and ...