str_replace & foreach or preg_replace

Now, usually the obvious choice is str_replace, but I'm dealing with an array of maybe 40 - 50 elements here out of which only a couple will actually be in the text I'm replacing them in.

What is more efficient? Looping through a bunch of times, even if many are unsuccessful or using regular expressions?

thanks

 

str_replace, with almost 100% certainty.

Would have to be very odd for regular expressions to be faster.

 

While Loop over for loop, my two cents, will enable to keep some memory from wasting.

 

alright, thanks for the input. I thought so. I guess I'll castrate the array before passing it to the loop as well.