PHP variable interpolation vs concatenation

Question

What is the difference between the two following methods (performance, readability, etc.) and what do you prefer?

echo "Welcome {$name}s!"

vs.

echo "Welcome " . $name . "!";

Solution

Whatever works best for you works... But if you want to go for speed use this:

echo 'Welcome ', $name, '!';

The single quotes tell PHP that no interpretation is needed, and the comma tells PHP to just echo the string, no concatenation needed.

Comments

[Rich Remer]

The speed difference between single and double quotes is a myth (at least with versions of PHP released this millenium) phpbench.com

[Borniet]

My reference to the speed was by using the comma instead of the dot, which is (marginally) faster. And that's also backed by the link you provided. Very interesting link btw!!!

[totymedli]

The performance difference is literally microseconds! On the other hand echo "Welcome $name!"; is many times more readable.

[Kick_the_BUCKET]

@Borniet the conclusion does say that using commas with echo is faster, but the result above that conclusion prove otherwise.

[Shayne]

I should note string interpolation is a bad habit to be in, in general. If you use it with SQL, of course, your DBA will curse the earth you walk on, and your security consultant will clamor for your retrenchment. Its bad bad news (Always, always use prepared statements, or a battle tested ORM)

[ksadowski]

@Shayne It's quite a jump from string interpolation in SQL being a bad, bad habit (I wholeheartedly agree!) to string interpolation in general being a bad habit. I personally find it more readable (less messy) than concatenation, and use it wherever applicable. Are there any strong arguments against string interpolation in general?

[Shayne]

Not really but i feel it needs to a warning visible to anyone learning about string interpolation, that there are a number of circumstances where the whole thing can get very ugly (with SQL, handling HTML and passing strings to external prcoesses being the big security dangers)

[philomory]

@shayne The SQL argument is completely irrelevant to the question, string concatenation is exactly as bad as interpolation, and for exactly the same reasons, in an SQL context.

[Shayne]

I never said it wasn't. You should never use any of those in SQL.