define varibale

[Destramic]

im having a problem getting this code to work...i know it may not make sence why i would do this but it is for a larger script...is there any reason why it wont echo please?

define ('TEST_VAR', 'hello');
$var = "TEST";
echo {$var}_VAR;

[Psycho]

The brackets {} are only used within a double quoted string (or hredoc method) to have a variable interpreted. One of the following methods would work (I'd go with the first)

echo $var._VAR;

echo "{$var}"._VAR;

 

EDIT: Scratch that. I misread what you were trying to do. You are defining a constant and then trying to access that constant dynamically. I don't know of a way to do that. You could instead define the TEST_VAR as an array

$config = array();
$config['TEST_VAR'] = 'hello';
$var = "TEST";
echo $config["{$var}_VAR"];

[BlueSkyIS]

actually, you can use the brackets to create a dynamically named variable

 

$var = 'hello';
${$var} = 'world';
echo $hello;

 

output: world

 

but i can't get this to work properly to dynamically define a constant.

[Psycho]

OK, a quick search shows a solution using constants

define ('TEST_VAR', 'hello');
$var = "TEST";
echo constant("{$var}_VAR");
//Output: hello

[Destramic]

thanks guys...wouldnt know what i'd do without you

[BlueSkyIS]

OK, a quick search shows a solution using constants

define ('TEST_VAR', 'hello');
$var = "TEST";
echo constant("{$var}_VAR");
//Output: hello

 

thanks for that. good to know. i was stumped.

[Psycho]

OK, a quick search shows a solution using constants

define ('TEST_VAR', 'hello');
$var = "TEST";
echo constant("{$var}_VAR");
//Output: hello

 

thanks for that. good to know. i was stumped.

 

Yeah I had no idea either. But, it was right there in the manual for constants! Who would have thought to look there?