Iterative Control Structures
Iterative control structures, including do-while, for, foreach, and while loops, provide the programmer with a key tool by enabling a program to repeat a set of instructions a specified number of times or until a condition is met.
There are different structures because you can have different purposes when you want to step through data repeatedly. Sometimes you want to do it until a condition is met, as is accomplished with the for and do-while loops. On occasion you want to gate entry to an iterative structure with a condition, which is what the while loop does. In the case of a hash table or hash map, which manages a key-to-value index, PHP provides a special iterative structure—the foreach loop.
In the following ...