Groups > microsoft.public.scripting.vbscript > #12330

Re: Why does a loop using instr() and mid() get slower on larger data ? - found it (I think)

From	"R.Wieser" <address@not.available>
Newsgroups	microsoft.public.scripting.vbscript
Subject	Re: Why does a loop using instr() and mid() get slower on larger data ? - found it (I think)
Date	2021-01-03 08:58 +0100
Organization	Aioe.org NNTP Server
Message-ID	<rsrtfa$1v8c$1@gioia.aioe.org> (permalink)
References	(1 earlier) <rspt2m$613$1@dont-email.me> <rsq4fr$2tr$1@gioia.aioe.org> <rsqku7$ksc$1@dont-email.me> <rsqnho$157m$2@gioia.aioe.org> <rsqs1f$5le$1@dont-email.me>

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Mayayana,

>  I don't know. InStr is incredibly fast. I suspect the
> wrapper bloat is much of the time.

Yesterday, ofcourse just after I called it a night and switched my 'puter 
off, I got a brainfart.   Just now I tested it.

You mentioned caseless searching, and that is what I have been doing (and 
forgot to mention, sorry).   Changing that last InStr argument back to 
casefull searching sped the whole process up considerably.

What I think that happens is that InStr() first converts both strings to 
either upper or lower case, and only than does the search.    While that 
isn't a problem for relativly short strings, the conversion does take some 
time when you throw 25 MB at it ...

... especially when you do that in a loop which finds over 40,000 .

Hence that reading the file line-by-line and than doing the caseless InStr() 
sped the process up.

The whole process using the 25 MB string still takes several seconds to 
complete though.  Oh well.

Regards,
Rudy Wieser

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Thread

Why does a loop using instr() and mid() get slower on larger data ? "R.Wieser" <address@not.available> - 2021-01-02 12:41 +0100
  Re: Why does a loop using instr() and mid() get slower on larger data ? "Mayayana" <mayayana@invalid.nospam> - 2021-01-02 08:39 -0500
    Re: Why does a loop using instr() and mid() get slower on larger data ? "R.Wieser" <address@not.available> - 2021-01-02 16:46 +0100
      Re: Why does a loop using instr() and mid() get slower on larger data ? "Mayayana" <mayayana@invalid.nospam> - 2021-01-02 15:26 -0500
        Re: Why does a loop using instr() and mid() get slower on larger data ? "R.Wieser" <address@not.available> - 2021-01-02 22:11 +0100
          Re: Why does a loop using instr() and mid() get slower on larger data ? "Mayayana" <mayayana@invalid.nospam> - 2021-01-02 17:27 -0500
            Re: Why does a loop using instr() and mid() get slower on larger data ? - found it (I think) "R.Wieser" <address@not.available> - 2021-01-03 08:58 +0100
              Re: Why does a loop using instr() and mid() get slower on larger data ? - found it (I think) "Mayayana" <mayayana@invalid.nospam> - 2021-01-03 08:54 -0500
                Re: Why does a loop using instr() and mid() get slower on larger data ? - found it (I think) "R.Wieser" <address@not.available> - 2021-01-03 16:01 +0100
                Re: Why does a loop using instr() and mid() get slower on larger data ? - found it (I think) "Mayayana" <mayayana@invalid.nospam> - 2021-01-03 12:51 -0500
                Re: Why does a loop using instr() and mid() get slower on larger data ? - found it (I think) "R.Wieser" <address@not.available> - 2021-01-03 19:26 +0100
          Re: Why does a loop using instr() and mid() get slower on larger data ? "Mayayana" <mayayana@invalid.nospam> - 2021-01-02 17:43 -0500
  Re: Why does a loop using instr() and mid() get slower on larger data ? JJ <jj4public@gmail.com> - 2021-01-03 02:47 +0700
    Re: Why does a loop using instr() and mid() get slower on larger data ? "R.Wieser" <address@not.available> - 2021-01-02 21:47 +0100

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