perl program to validate user input by comparing existing array - perl

Question

Im trying to write a Perl script to validate user input.
If the user provide wrong value then it should show which is wrong value among the provided user input.
Example:
I have any array #arr=qw/cat rat mat sat/;
If user provide the input as perl validate_user_input.pl cat sot bat then, my script should show sot bat is wrong inputs to the script.
below is the script im trying .
#!/usr/bin/perl
use strict;
use warnings;
my (#not,#arr,$flag);
#arr=qw/cat rat mat sat/;
my $count=#arr;
foreach (#ARGV)
{
my $i=1;
foreach my $existing (#arr)
{
until ( "$existing" eq "$_" )
{
$flag = 1;
$i++;
last;
}
}
print "$i\n";
if ( ($count==$i) && ($flag == 1))
{
push(#not,"$_");
}
}
print "#not\n";
Logic i tried to implement:
Element in #ARGV will be checked against each element of #arr. If $flag=1 and the iteration $i is equal to number of elements in #arr (i.e checked against all the elements in #arr) then input not found in #arr.
Can anyone tell me what need to be done for this script to work.

Answer 1

Too complicated. Turn your 'valid' args into a hash, then use grep:
#!/usr/bin/env perl
use strict;
use warnings;
my #allowed = qw/cat rat mat sat/;
my %is_allowed = map { $_ => 1 } #allowed;
foreach my $arg ( grep { not $is_allowed{$_} } #ARGV ) {
print "$arg is not valid\n";
}
You can set a flag in that foreach loop if you like, if you want to proceed. Or just use grep in a scalar context:
if ((grep { not $is_allowed{$_} } #ARGV) > 0 ) {
die "invalid args found, exiting\n"
}

Answer 2

Well, a short search of this site would lead me to believe you are over-complicating things:
#!/usr/bin/env perl
use strict;
use warnings;
my (#not,#arr);
#arr=qw/cat rat mat sat/;
foreach (#ARGV)
{
push(#not,"$_") unless ( "$_" ~~ #arr );
}
print "#not\n";
The smart match operator (~~) still comes back as 'experimental' on my 5.24 version of bash, but it would seem it has been around since at least 5.10.
You may also want to add some kind of test at the end to check if #not has anything in it as all words may have been found. You could re-use your flag :)

Answer 3

Put the valid arguments into a hash %valid (instead of an array #arr). Then you can do:
for (#ARGV) {
push #not, $_ if !exists $valid{$_};
}

Answer 4

TIMTOWDI
use strict;
use warnings;
my #arr=qw(cat rat mat sat);
my $ok = { map{ $_ => 0 } #arr};
my $wrong;
exists $ok->{$_} ? $ok->{$_}++ : $wrong->{$_}++ for #ARGV;
print "OK $_ : $ok->{$_}\n" for #arr;
print "NO $_ : $wrong->{$_}\n" for (sort keys %$wrong);
using
perl arg.pl bat cat ded rat mat foo bar foo cat
output
OK cat : 2
OK rat : 1
OK mat : 1
OK sat : 0
NO bar : 1
NO bat : 1
NO ded : 1
NO foo : 2