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What is Casting a Data Type in PHP?

Posted: Thu Mar 12, 2009 11:00 am
by pankajdeoria
Hello Friends,
I am Pankaj Gupta .Can you please tell me in detail What is Casting a Data Type in PHP :?: ? I am a new user to this forum and PHP too.

Thank You.

Re: What is Casting a Data Type in PHP?

Posted: Thu Mar 12, 2009 2:21 pm
by pickle
Casting is using a language construct to change the type of a variable.

For example:

Code: Select all

$var = 1.223;
$var2 = (int)$var;
 
//$var2 now = 1
This doesn't necessarily work between all data types.

Re: What is Casting a Data Type in PHP?

Posted: Thu Mar 12, 2009 6:08 pm
by panic!
you can cast a function or method's arguments too.

Code: Select all

 
 
 
class cat
{
 
}
 
class dog
{
 
 
}
 
function cats_only(cat $xyx)
{
 
 
}
 
$jess=new cat();
$rover=new dog();
 
cats_only($jess); // works
cats_only($rover); //epic fail
 
 

Re: What is Casting a Data Type in PHP?

Posted: Thu Mar 12, 2009 6:26 pm
by Chris Corbyn
panic! wrote:you can cast a function or method's arguments too.

Code: Select all

 
 
 
class cat
{
 
}
 
class dog
{
 
 
}
 
function cats_only(cat $xyx)
{
 
 
}
 
$jess=new cat();
$rover=new dog();
 
cats_only($jess); // works
cats_only($rover); //epic fail
 
 
That's not type-casting and is misleading. It's type-hinting.

Type-casting is taking something that's one type and making it behave like it's another. The types must be compatible though.

PHP can also only type-cast between it's own primitive types, it can't type-cast say Cat to Animal and Vice-versa if you have those classes.

Re: What is Casting a Data Type in PHP?

Posted: Sat Mar 14, 2009 11:46 pm
by josh
Chris Corbyn wrote:PHP can also only type-cast between it's own primitive types, it can't type-cast say Cat to Animal and Vice-versa if you have those classes.
And just for the record you don't need to since PHP is dynamically typed ( I know you know that Chris but posting for OP )

Re: What is Casting a Data Type in PHP?

Posted: Tue Mar 17, 2009 12:38 pm
by panic!
Oh! My bad.

Re: What is Casting a Data Type in PHP?

Posted: Wed Mar 18, 2009 12:10 am
by josh
panic! wrote:Oh! My bad.
Well that wasnt towards you, I was saying about type casting not type hinting

Re: What is Casting a Data Type in PHP?

Posted: Wed Mar 18, 2009 5:51 am
by Hadi
pleae check this link i hope it will be useful :
http://www.talkphp.com/tips-tricks/1499 ... types.html