how to add the output of an echo() to a variable for later use

marcnyc

Is there a way to do this?
let's say I have:

function echo_this () {
   echo 'test';
}

and I want to add "test" inside a variable rather than seeing it output when I call echo_this();
is that possible?

I know I should be adding a $var inside the function and then do 'return $var;' but I can't modify that part of this script because it would have too many implications across the script. Somebody told me there is a way to add the output of an echo to a variable for later use but I can't find anything in the manual.

Can you suggest a workaround?

Thanks

dagon

somebody, was probably talking about Output Control Functions which are generally used poorly.

if you don't want to edit this function why not create another function that does assign to a var and return the var. It's generally recommended not to use echo in a function but to return the value and echo it outside of the function anyway.

bradgrafelman

You can always edit the function such that it will be backwards compatible and not break old code. For example, take your function you posted above:

function echo_this () { 
   echo 'test'; 
}

You can modify it to return the data instead of outputting it while ensuring that it won't affect old code like so:

function echo_this ($output = TRUE) { 
   if($output)
      echo 'test';
   else
      return 'test';
}

marcnyc

what is that '($output = TRUE)' and how do I use it? I never encountered that?

I know that using return in a function is more versatile than echo, but is it not true that echo makes the script using the function faster (less code lines) and that it frees up memory because no variables need to be stored?

Weedpacket

marcnyc wrote:
what is that '($output = TRUE)' and how do I use it? I never encountered that?

That's described here.

I know that using return in a function is more versatile than echo, but is it not true that echo makes the script using the function faster (less code lines) and that it frees up memory because no variables need to be stored?

That's kind of irrelevant if the function doesn't do what's required, isn't it?

bradgrafelman

marcnyc wrote:
what is that '($output = TRUE)' and how do I use it? I never encountered that?

It's similar a function parameter that's been given a default value. Thus, if you don't specify the parameter's value in a call to the function (e.g. your old code, which wouldn't have a value for it) then PHP will assign this default value to the the parameter.

See this section in the manual for more information on default values in functions.

marcnyc wrote:
is it not true that echo makes the script using the function faster (less code lines) and that it frees up memory because no variables need to be stored?

First of all, less code lines does not imply that a PHP script will run faster.

Second, the amount of memory we're talking about is probably in the order of a few bytes... nothing to write home about.

marcnyc

Yes you are right about that, however I had to have my script drastically optimized because servers couldn't deal with it any longer and so converting all return functions into echo functions was one of the steps my webmaster took. Wouldn't you agree that on a large script it might make a difference when there are many functions used many times?

Weedpacket

The difference that change would make would be on the order of 100ns per call. You wouldn't notice it next to the time it would take to package the output bytes for transport over the network.

You'd save more time if you didn't use the function at all, and replaced calls to it with its body. But it would still be microscopic. And certainly not "drastic".

bradgrafelman

marcnyc wrote:
Wouldn't you agree that on a large script it might make a difference when there are many functions used many times?

No, not if you re-use variables or set them to NULL and [man]unset/man them after you're finished using them.