Question

Regarding performance, is there any difference between doing:

$message = "The request $request has $n errors";

and

$message = sprintf('The request %s has %d errors', $request, $n);

in PHP?

I would say that calling a function involves more stuff, but I do not know what’s PHP doing behind the scenes to expand variables names.

Thanks!

Answer 1

In all cases the second won’t be faster, since you are supplying a double-quoted string, which have to be parsed for variables as well. If you are going for micro-optimization, the proper way is:

$message = sprintf('The request %s has %d errors', $request, $n);

Still, I believe the seconds is slower (as @Pekka pointed the difference actually do not matter), because of the overhead of a function call, parsing string, converting values, etc. But please, note, the 2 lines of code are not equivalent, since in the second case $n is converted to integer. if $n is “no error” then the first line will output:

The request $request has no error errors

While the second one will output:

The request $request has 0 errors