I've always considered print() and echo() interchangeable and never seen any clues that either did something different than the other.

Is there a difference between print() and echo()? Is one intended for certain cases the other isn't? Or.... ?

Just curious. Thanks.


PS While I'm asking dumb questions, I've read that include() is supposed to be used in conditional situations, whereas require() should be used in non-conditional ones. I pretty much always used require() regardless of the context. Is this a problem, or does it even really matter?

Thanks again.

From what I understand, echo() is slightly faster than print(). However, the difference is probably insignificant.

One thing though, if you want to echo() a large block of code, like a table or something, I've heard that instead of doing this:

PHP Code:

echo '<table>';
echo '<tr><td>';
echo 'this is inside the table cell';
echo '</td></tr>';
echo '</table>'; 


it's faster to put everything into a string variable, i.e. $table, and then echo $table once at the end:

PHP Code:

$table = '<table>';
$table.= '<tr><td>';
$table.= 'this is inside the table cell';
$table.= '</td></tr>';
$table.= '</table>';

echo $table; 


I've heard that that's faster than calling echo() multiple times.

Phaedrus, I'm not sure why it would be "faster" to do what you describe. The system still must handle the string concatenation that you describe.

However, I would stress that even if one echo command does save some time over numerous ones, the advantage would be insignificant.

All of your questions can be answered correctly at their corrosponding pages in the PHP manual (www.php.net/function_name).

echo will be a little bit faster because it will not return a value. The difference in speed, however, would be insignificant as Phaedrus stated.

print is good when you need to use it as a function, for example:

PHP Code:

while(print("Here we go again"))
{
    // ...
}

// or
$something = $myvar > 2 ? print("Success!") : false; 


As to your example Phaedrus, I would think it would be faster to echo the entire string out at once because you don't have to write the string to the variable memory first, then access it again upon print. The few lines of the table in your example probably wouldn't save or spend any time either way. But if you are working with hundreds of lines, you could probably shed a few hundredths of microseconds off

This seems to answer this topic pretty well...

http://www.faqts.com/knowledge_base/...l/aid/1/fid/40

Just to say about require and include.

require() (or require_once()) means that if it cannot include it for what ever reason the whole script will stop and return error.

Include (or include_once()) means it will try and continue running even if PHP cannot load the file.

As far as i know neither nor is specifically used in loops or switches although often they are.

Usually i would say require would be good for things like config files which have to be loaded where as if the file to be used is something like a template file maybe include would be better.

Also incase you were wondering require/include_once() means IF it hasnt already been loaded before load it if it has dont, usually helpful for things like functions files so it doesnt cause reclassification errors where it tries to make a function twice.

Hope this helps

TP appriciarted if it did

Originally Posted by gregory

PS While I'm asking dumb questions, I've read that include() is supposed to be used in conditional situations, whereas require() should be used in non-conditional ones. I pretty much always used require() regardless of the context. Is this a problem, or does it even really matter?

It only matters if you intend to require a file that might be missing -- which shouldn't ever be the case -- in which case your program will immediately halt execution; whereas with include you have the ability to determine if there was an issue and decide what to do from there.

For what it's worth, I see way too many PHP apps using include(), and providing no error notification, when they should be using require(). Similarly, the value of the require_once() and include_once() functions shouldn't be under-estimated.

require() will throw a fatel error on failure (and the current php parser will die) and include() will only issue a warning on failure.