php echo variables that haven't happened yet.

[ChenXiu]

When a variable hasn't happened yet, what's the best way?
To use a function? To use ob_start()? Or something else?
 

if( $condition == true ){
$instruction = ' hello do this. ';
} else {
$instruction = " $variable_set_later ";
}
//code
//code
//now we set that variable
$variable_set_later = 'hello do something else';
//
//
echo $instruction;

 

[ChenXiu]

Nevermind. I figured it out.
"sprintf()"