One of the key concepts in computer programming is looping or repetition. This is because it allows the user to carry out an endless number of instructions while a certain condition is true. For example on this forum we load a page of posts using a loop to cycle through the data and place it into the template. In this tutorial we will learn a few of the commonly used methods of looping in PHP.

Loopy Looping!
Firstly we will learn how to use a for loop. This should not be confused with the foreach loop we'll learn later in this tutorial.


In the above piece of code you can see the logical structure of the statement. The first value labelled start is where we define the variable that will be used to count through the loop. The condition is the same as an if logic statement. While the condition evaluates to true the loop will repeat over again. Finally the change is what we should do to the variable to make the loop exitable.

Here is a real example with exampler values.


In this example we start the loop with x being set to 1. Each time the loop runs we increase the value of x by one, and the condition, it will repeat while x is less than 1000.

The example below uses $x++ which is another way of increasing the value of x by 1.


This code gives the following output.


Using a while or do while loop.
The code below works like this. While the the variable stop is not set it will continue to loop. The variable stop is set only when the number chosen at random is 123.


Rather than using variable's to control loops we can use the break statement. This will exit any loop that is currently running. The below code also demonstrates this.


The do while loops is slightly different because the loop always runs once whether or not the condition was true the first time around.


Using the foreach loop!
The foreach loops is used when arrays are concerned. In these tutorials we havn't covered arrays much yet so we'll keep this example short.


We will come back to foreach loops once we have covered more on arrays.

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