Mid vs Mid$

According to the documentation in VB6 the Mid function returns a variant, but Mid$ returns a string and apparently this is more efficient.

My questions are :

1. What simple test can I use to discern the difference in performance ? I tried looking at simple app which did a few string operations, with Perfmon, but there was no discernible difference.

2. Is it worth worrying about? I've gotten into the habit of using the $-ized functions, but should I recommend everybody on my team to use it as well ?

From stackoverflow

• Isn't worth worrying about. It's a remnant from Microsoft Basic of 15-20 years ago when a fast processor was orders of magnitude slower than anything today.

  It has a certain esthetic appeal to use Mid$ rather than let VB determine what your datatypes are, though. And if you have any loops that are executing it, say, thousands of tiems a second, then your curiosity factor might increase. Otherwise, neh.

  Here's a link to someone who measured the difference. Mid$ was about 2.5 times as fast as Mid. Including tests going back to VB4.

  jakdep : Thanks. Interesting link, exactly what I was looking for.

  garykindel : Might want to consider including a 3rd party library like Stamina. Includes many string handling routines written in C that are much faster than VB6. http://www.hallogram.com/stamina/routines.html

• Honestly, I think it's negligible.

  Maybe you can try something like this. Download the "High-Performance Timer Object" from http://ccrp.mvps.org/, do a long loop (1.000.000 iterations or so) of string operations, and measure the run time difference. By "operations" I mean: Concatenation of Variants as opposed to concatenation of Strings. Mid() and Mid$() will very likely perform the same. OTOH - you can test that as well.

  If you did, I'd be interested if you posted the results.

  jakdep : +1 for the Timer Object link. I compared Mid("ABC") with Mid$("ABC"), as in the link provided by le dorfier, over 100,000,000 iterations and measured the duration with High-Performance stopwatch. Mid() took 35.364 seconds and Mid$() took 13.56 seconds. So, it matches the results shown in the link.

  jakdep : *cough* *cough* Sorry, that is +1 if I could upvote it.

  Tomalak : I am surprised. This really *is* a mentionable difference.

• Whilst performance between them is negligible its not really a differentiator as to which to use anyway.

  There can be some nuances when using a variant when a strong type is required. For example what happens when you pass a variant to a parameter expecting a ByRef string? Nothing bad but something a little more than passing an address happens.

  Hence if you know that you want to work with strings then go ahead and use the $ versions of these functions the behaviour of them and their use in other expressions is simpler and better understood. If you know you need a variant and your inputs are variants then sure use the non $ versions.

  mafutrct : Exactly! Variants should be avoided whenever possible.