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Full Discussion: Random Line
Top Forums Shell Programming and Scripting Random Line Post 31875 by Perderabo on Thursday 14th of November 2002 10:47:56 AM
Old 11-14-2002
Suppose that you want to pick a random line froma file that has exactly 100 lines. You can label the lines 0 through 99. Then if you get a random integer, you just take the last two digits as your line number.

Those last 2 digits are the remainder that your get when you divide the random integer by 100. So for example, if the random integer is 10726352; you would have a remainder of 52 after dividing 10726352 by 100. This is expressed as
10726352 % 100 = 52
and % is sometimes called "the remainder function". And sometimes "modulus".

But is was important to divide by 100 since we had 100 lines in our file. When we divide by 100, we have 100 possible remainders, so each line in the file has a chance.

To make this general, don't divide by 100 (or 50) all the time, divide by the count of items.
 

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LEARN ABOUT SUSE

gsl-randist

GSL-RANDIST(1)						      General Commands Manual						    GSL-RANDIST(1)

NAME

       gsl-randist - generate random samples from various distributions

SYNOPSYS

       gsl-randist seed n DIST param1 param2 [..]

DESCRIPTION

       gsl-randist  is a demonstration program for the GNU Scientific Library.	It generates n random samples from the distribution DIST using the
       distribution parameters param1, param2, ...

EXAMPLE

       Here is an example.  We generate 10000 random samples from a Cauchy distribution with a width of 30 and histogram them over the range  -100
       to 100, using 200 bins.

	    gsl-randist 0 10000 cauchy 30 | gsl-histogram -100 100 200 > histogram.dat

       A  plot	of  the  resulting histogram will show the familiar shape of the Cauchy distribution with fluctuations caused by the finite sample
       size.

	    awk '{print $1, $3 ; print $2, $3}' histogram.dat | graph -T X

SEE ALSO

       gsl(3), gsl-histogram(1).

AUTHOR

       gsl-randist was written by James Theiler and Brian Gough.  Copyright 1996-2000; for copying conditions see the GNU General Public Licence.

       This manual page was added by the Dirk Eddelbuettel <edd@debian.org>, the Debian GNU/Linux maintainer for GSL.

GNU
																    GSL-RANDIST(1)
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