str_replace with strpos?

Question

The str_replace function with a strpos checking can avoid extra work?

METHOD 1

...
if (strpos($text, $tofind) !== FALSE)
 $text = str_replace($tofind, $newreplace, $text);
...

METHOD 2

...
$text = str_replace($tofind, $newreplace, $text);
...

Question: This two methods works but... I want know if strpos-checking (or other) is good way or a bad, useless (and optimization antipattern).

Answer 1

You may save some str_replace() calls, but you get always additional strpos()-calls and !== false comparisons. However, I don't think, that it will make any measureable impact, as long as this code will not run around 100000 times (or such). Thus as long as you don't need to know, if there are replacements to made, you should avoid this "optimization" to keep things more simple and readable.