Comments on: Get random numbers under BASH and DOS http://9rivers.linkka.com/2010/03/01/get-random-numbers-under-bash-and-dos/ Molecular modeling in Materials Sciences Web development Programming IT Mon, 20 Jun 2011 09:37:31 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: 9rivers http://9rivers.linkka.com/2010/03/01/get-random-numbers-under-bash-and-dos/comment-page-1/#comment-508 9rivers Fri, 18 Feb 2011 11:45:25 +0000 http://9rivers.linkka.com/?p=357#comment-508 Aha! random, you are in trouble with the so-called "delayed variable expansion" in DOS batch. This has been discussed here: http://blogs.msdn.com/b/oldnewthing/archive/2006/08/23/714650.aspx . In your case, in order to get 100 DIFFERENT random numbers, you have to enable the delayed variable expansion for your DOS console. Do this "cmd /v" to start it, or add this "setlocal enabledelayexpansion" in your batch file. Then, another important thing is to change the "%" symbol to "!" for the variables you want them to be expanded on the fly. E.g. try "FOR /L %%a IN (0,1,100) DO @echo !RANDOM!" in your file, you'll get 100 DIFFERENT random numbers! Aha! random, you are in trouble with the so-called “delayed variable expansion” in DOS batch. This has been discussed here: http://blogs.msdn.com/b/oldnewthing/archive/2006/08/23/714650.aspx .

In your case, in order to get 100 DIFFERENT random numbers, you have to enable the delayed variable expansion for your DOS console. Do this “cmd /v” to start it, or add this “setlocal enabledelayexpansion” in your batch file. Then, another important thing is to change the “%” symbol to “!” for the variables you want them to be expanded on the fly. E.g. try
“FOR /L %%a IN (0,1,100) DO @echo !RANDOM!” in your file, you’ll get 100 DIFFERENT random numbers!

]]> By: random http://9rivers.linkka.com/2010/03/01/get-random-numbers-under-bash-and-dos/comment-page-1/#comment-505 random Thu, 10 Feb 2011 19:58:35 +0000 http://9rivers.linkka.com/?p=357#comment-505 What about use %RANDOM% inside FOR in ms-DOS ex: FOR /L %%a IN (0,1,100) DO @echo %RANDOM% I would generate 100 DIFFERENT random numbers but the line above generates 100 times the same number!!! What's up? What about use %RANDOM% inside FOR in ms-DOS
ex:
FOR /L %%a IN (0,1,100) DO @echo %RANDOM%
I would generate 100 DIFFERENT random numbers but the line above generates 100 times the same number!!! What’s up?

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