podedo podedo - 1 day ago 5
Perl Question

Generating limited amount of random numbers in Perl for a known range

I have a file

letters.txt
which has couple letters

@string1 10 letters

A H K Y M H O L H L

@string2 9 letters

H N U P W X L Y H


I am trying to create a file which will have random numbers from 20 to 60 for each letter, for each string.

My expected output should look like :

output.txt:



@string1

29 27 56 43 39 40 36 48 59 38

@sting2

26 36 39 39 26 51 38 42 42


I have tried the code below with
$minimum
as 20 and
$maximum
as 60:

open ($fh, '>', $fileToLocate) or die;

my $x = $minimum + int(rand($maximum - $minimum);

print $fh "$x\n";

close $fh;


It creates only one random number in
$fileToLocate
file.

I want to extract the number of letters in each string — written just before
letters
in the input file: 10 for
@string1
and 9 for
@string2


I have tried to this code to create 30 random numbers ranging between 20 and 60, however it did not work out

my @Chars = ( 20 .. 60);

$RandString = join("", @Chars[ map { $x } ( 1 .. 30 ) ]);

print $fh "$RandString\n";

close $fh;

Answer

You're close.

The code to pick a random number from $min to $max looks like this.

my $rand = $min + int rand($max - $min + 1));

So you had that part right, but with an off-by-one error (I made the same mistake earlier). Because rand starts at 0, int rand $x will go from 0 to $x - 1.

Then you need to generate a bunch of them. You're close with the map, but $x only stores a single random number, so map { $x } ( 1 .. 30 ) will just give you one number repeated 30 times. Instead you need to get a new random number inside the map block.

my @rands = map { $min + int rand($max - $min + 1)) } 1..length $string;

That will run int($x + rand($y-$x)) for a number of times equal to the number of characters in $string and put them all into the list @rands. Then you can join @rands like you have already.

print $fh join '', @rands;

That should get you the rest of the way.

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