I tried the php code for the last episode for the form and got the following error messages when ...

[G+_Matthew Reardon]

Coding 101 - PHP

 

I can count!

 

 

<?php

 

$limit = $_GET["number"];

 

$count = 1;

 

while ($count <= $limit) {

    echo "$count

\n";

    $count++;

}

 

?>

 

[G+_Nate Follmer]

So is this code causing the errors or are these errors only appearing when you dont have the $count = 1; line? Only asking because you said if you set the variable before the loop, it works.

 

Even though PHP is a bit loose with it's variables, you still should define them before you use them. It will avoid things like this.

 

Edit: I should stop commenting before coffee... Let me make that wall of text into a TL;DR:

 

You can't use variables in a conditional statement without first defining them :) ?

[G+_Matthew Reardon]

Right, when count is not defined ($count=1) before the loop it throws the errors.

[G+_Nate Follmer]

Yeah so to use a variable in a conditional statement you must "define" it first or in your case define and assign the value 1. You can hide those notices, but it's best not to, as it's telling you there is a possible bug in your code.

[G+_Jeff Brand]

PHP has different levels of complaints.

Fatal, Warning, Notice, (and more.)

 

Notices, most often when trying to access an undefined variable are usually hidden in shared hosting environments.  Some developers like myself had developed bad habits such as undeclared variables over the course of years. (That's a stark contrast to my ASP classic days where Option Explicit was always the first line.)

 

To be accurate, Nathan Follmer , you can use an unset variable in a conditional statement but it will evaluate as false.

 

Type comparison in PHP is loose, as with many scripting languages. While pages like (http://php.net/manual/en/types.comparisons.php) aren't necessary for the beginner to fully understand, a general understanding of when PHP might think something is FALSE can prevent lots of frustration and bugs.

 

These days I try to enable all messages during development and hide them in production, while still logging them to the error logs.

 

Further best practices:

* Declare variables early, even if it's to false, 0, empty string, or null.

* Use isset(), empty(), or defined() (for constants) to check for unset elements while avoiding Notices

* Wrap your code in a function to separate your variables from the global variable space

 

Perhaps that last one will be covered in a future episode..