Re: [PHP] Overwrite value of true or false in PHP
On Mon, 2009-09-07 at 19:14 +, Bobby Pejman wrote: Hi, I noticed that the following returns a 1. echo (12) ? True : False I was under the impression that true/false are of type boolean and not int. But in php anything other than 0 translates to true, meaning a 1. What I am trying to achieve is for a 1 to be a 1 and a true or false to be a true and false respectively and I do not want to put quotes around the word true/false either because then it is no longer a boolean but string. Is it possible to overwrite php's true/false and declare them as boolean? You often see in C++, some use Define(). Thanks. The statement you gave does return a boolean value, but what you are doing is printing the resulting value out. PHP converts the boolean to the nearest printable value, which will be a 1 or 0. If you want it to output the value 'True' or 'False' then you need to output a string value. Thanks, Ash http://www.ashleysheridan.co.uk -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Overwrite value of true or false in PHP
On Mon, Sep 7, 2009 at 4:14 PM, Bobby Pejman bpej...@gmail.com wrote:
Hi,
I noticed that the following returns a 1.
echo (12) ? True : False
I was under the impression that true/false are of type boolean and not int.
But in php anything other than 0 translates to true, meaning a 1. What I
am trying to achieve is for a 1 to be a 1 and a true or false to be a true
and false respectively and I do not want to put quotes around the word
true/false either because then it is no longer a boolean but string.
Is it possible to overwrite php's true/false and declare them as boolean?
You often see in C++, some use Define().
Thanks.
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
Yes *true* and *false* are booleans.
PHP convert natively different types to boolean in order to help write
sentences like this
if( $object )
{
$object-something();
}
while( $data = mysql_fetch_assoc( $resource ) )
{
print_r( $data );
}
But we you try to print a boolean variable PHP convert it to string: true
becomes '1' and false becomes ''. That's why you can't just echo a boolean
variable to see the value, but you can rely on var_dump to show this.
$bool = true;
echo $bool;
var_dump( $bool );
$bool =! $bool;
echo $bool;
var_dump( $bool );
As other languages PHP as an special operator for checking types while
comparing values.
$a = 'false';
$b = true;
var_dump(
$a == $b, # -- true
$a === $b # -- false
);
This happens because values are converted before comparison so, 'false'
becomes true.
PHP converts everything different to an empty string as *true*
This also affect any type of variable.
--
Martin Scotta
Re: [PHP] Overwrite value of true or false in PHP
On Mon, Sep 7, 2009 at 4:19 PM, Ashley Sheridan a...@ashleysheridan.co.ukwrote: On Mon, 2009-09-07 at 19:14 +, Bobby Pejman wrote: Hi, I noticed that the following returns a 1. echo (12) ? True : False I was under the impression that true/false are of type boolean and not int. But in php anything other than 0 translates to true, meaning a 1. What I am trying to achieve is for a 1 to be a 1 and a true or false to be a true and false respectively and I do not want to put quotes around the word true/false either because then it is no longer a boolean but string. Is it possible to overwrite php's true/false and declare them as boolean? You often see in C++, some use Define(). Thanks. The statement you gave does return a boolean value, but what you are doing is printing the resulting value out. PHP converts the boolean to the nearest printable value, which will be a 1 or 0. If you want it to output the value 'True' or 'False' then you need to output a string value. Thanks, Ash http://www.ashleysheridan.co.uk -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php I think php convert the boolean variable to string before print its content. That's why... echo true; # prints '1' echo false; # does not prints anything, or prints '' $bool = false; var_dump( (string) $bool, (int) $bool ); -- Martin Scotta
Re: [PHP] Overwrite value of true or false in PHP
On Mon, Sep 7, 2009 at 3:14 PM, Bobby Pejmanbpej...@gmail.com wrote: Hi, I noticed that the following returns a 1. echo (12) ? True : False I was under the impression that true/false are of type boolean and not int. But in php anything other than 0 translates to true, meaning a 1. What I am trying to achieve is for a 1 to be a 1 and a true or false to be a true and false respectively and I do not want to put quotes around the word true/false either because then it is no longer a boolean but string. Is it possible to overwrite php's true/false and declare them as boolean? You often see in C++, some use Define(). Thanks. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php It might be pertinent for you to read the section of the manual dealing with type juggling: http://us3.php.net/manual/en/language.types.type-juggling.php and the various things linked therein. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Overwrite value of true or false in PHP
I see what's going on now. Because of the type conversion, I am writing my
code such that my return codes are translated to a strict 1 or 0. The idea of
having anything other than '' or 0 translating to a true scares me a little but
thanks for pointing out the === operator. I had to rewrite a lot of code after
discovering it. Good times...
Thanks for clarifying everyone.
-Original Message-
From: Martin Scotta martinsco...@gmail.com
Date: Mon, 7 Sep 2009 16:43:59
To: bpej...@gmail.com
Cc: php-general@lists.php.net
Subject: Re: [PHP] Overwrite value of true or false in PHP
On Mon, Sep 7, 2009 at 4:14 PM, Bobby Pejman bpej...@gmail.com wrote:
Hi,
I noticed that the following returns a 1.
echo (12) ? True : False
I was under the impression that true/false are of type boolean and not int.
But in php anything other than 0 translates to true, meaning a 1. What I
am trying to achieve is for a 1 to be a 1 and a true or false to be a true
and false respectively and I do not want to put quotes around the word
true/false either because then it is no longer a boolean but string.
Is it possible to overwrite php's true/false and declare them as boolean?
You often see in C++, some use Define().
Thanks.
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
Yes *true* and *false* are booleans.
PHP convert natively different types to boolean in order to help write
sentences like this
if( $object )
{
$object-something();
}
while( $data = mysql_fetch_assoc( $resource ) )
{
print_r( $data );
}
But we you try to print a boolean variable PHP convert it to string: true
becomes '1' and false becomes ''. That's why you can't just echo a boolean
variable to see the value, but you can rely on var_dump to show this.
$bool = true;
echo $bool;
var_dump( $bool );
$bool =! $bool;
echo $bool;
var_dump( $bool );
As other languages PHP as an special operator for checking types while
comparing values.
$a = 'false';
$b = true;
var_dump(
$a == $b, # -- true
$a === $b # -- false
);
This happens because values are converted before comparison so, 'false'
becomes true.
PHP converts everything different to an empty string as *true*
This also affect any type of variable.
--
Martin Scotta
