Can someone explain two snippets of code?

[bluegray]

Hi Php freaks =).

 

$testbox = isset($_POST['testbox'])?$_POST['testbox']:null;

 

I need to know what the "?" and the ":" are and how they work. 

 

Greatly appreciated.

[ram4nd]

if(isset($_POST['testbox'])) $testbox = $_POST['testbox'];

else $testbox = null;

[lostnucleus]

the above code is same as

 

if(isset($_POST['testbox']))
{
return $_POST['testbox'];
}else
{
return null;
}

 

if the code behind ? , returns true then $textbox is set to wat comes just after ? , if it return false then $textbox is set to wat comes after : .

[ram4nd]

Yes description is nice, but you wrote wrong code, mine is right. instead of your returns there should be $testbox =

[bluegray]

if(isset($_POST['testbox'])) $testbox = $_POST['testbox'];

else $testbox = null;

 

Perhaps I asked my question incorrectly. 

 

I understand how the code functions, but I've never seen the "?" or ":" defined or even used before.  What's the purpose of the if, else statement if we have "?" and ":" to use.  Additionally, I've learned whatever I know from Php books, yet have never seen these two operators offered as an alternative to the "if else" statement.  Is there a reason for this?

[ram4nd]

it makes the code shorter, but harder to read. Depends on taste. Why it exists, the question is rather why not.

[premiso]

It is called the Ternary Operator. Which as stated, it acts as a shortened if / else.

 

As for why it exists, it provides it uses. Namely, for the code you shown, which coincidently I wrote, allows for you to handle invalid / not passed in variables a bit easier without having to do a full on if statement. Some people prefer to use the full on if statement, but for simple assignments, why not use ternary? It does not detract from the code and a full on if statement is not usually needed as all you want to do is make sure that variable has a value assigned, namely for error testing purposes.

 

$name = isset($_POST['name'])?$_POST['name']:null;
$address = isset($_POST['address'])?$_POST['address']:null;

// VS: 
if (isset($_POST['name'])) 
    $name = $_POST['name'];
else
    $name = null;
if (isset($_POST['address']))
    $address = $_POST['address'];
else
    $address = null;

 

As stated, some people do not like it. I like it for assignments like the above, as it just makes sense to me to do it as such.

[lostnucleus]

@r4nd

yup return shd be replaced with the var name

 

One particular use of this snippet comes handy with phtmls , where you are coding view part of MVC ,

 

<?=  isset($this->memberName) ? $this->memberName : 'Welcome Guest'; ?>

 

[sspoke]

it should be used when it has to be used thats all.

 

It's not a oh I'll use this instread of if statements..

 

this is for shorting code that usually ends with a return call like fixing little things like money tax

 

$moneytax = ($money > 400) ? $money * 10 : 0;

shit like that but you see it always returns data.. thats why there is always a equals sign before it starts..

 

if statements don't return anything and in a if statment you'll have to declare $moneytax  2 times!

 

blah yah it doesnt make anything faster it makes code easier to read imo.

[ram4nd]

@r4nd

yup return shd be replaced with the var name

 

One particular use of this snippet comes handy with phtmls , where you are coding view part of MVC ,

 

<?=  isset($this->memberName) ? $this->memberName : 'Welcome Guest'; ?>

 

 

Word is that its not good to use <?= and <?, you should always use <?php.

I use template parser if I want to take advantage of View part in MVC.

 

Because only then HTML and PHP are truely separated.

[ignace]

@r4nd

yup return shd be replaced with the var name

 

One particular use of this snippet comes handy with phtmls , where you are coding view part of MVC ,

 

<?=  isset($this->memberName) ? $this->memberName : 'Welcome Guest'; ?>

 

 

That depends on how you model your application. I, for one always have a User object with the default name being Guest and rights set accordingly. So I would just write:

 

<?php echo 'Welcome, ', $this->memberName; ?>

[Daniel0]

@r4nd

yup return shd be replaced with the var name

 

One particular use of this snippet comes handy with phtmls , where you are coding view part of MVC ,

 

<?=  isset($this->memberName) ? $this->memberName : 'Welcome Guest'; ?>

 

 

Word is that its not good to use <?= and <?, you should always use <?php.

 

It's perfectly fine using those if you have control over the environment(s) that your PHP script will run it.

[ignace]

It's perfectly fine using those if you have control over the environment(s) that your PHP script will run it.

 

In case you don't understand by what he means with environment(s): you have access to the php.ini to configure allow_short_tags. However for portability and ease it's best to use <?php as this is guaranteed to always work.

[ram4nd]

I think he understands. And I get it if you change server you can simply run find and replace, but I guess it's my own weirdness. My point is that standards are good, thats just what i mean by that.