use warnings;
use strict;

for (qw(1 2 3 4 20.5 97 -5)) {
    if (($_ >= 1) and ($_ <= 75) and (!/\./)) {
        print "$_ yes\n";
    }
    else {
        print "$_ no\n";
    }
}

__END__

1 yes
2 yes
3 yes
4 yes
20.5 no
97 no
-5 no
[download]

The code works, just not in my context, which is much the same as mine, it seems to be something with pulling the value from between the keywords and putting it in $1 but that's what I need in this case. Toying a bit more I ended up with this, which works for my need even if a bit clumsy, can anyone shed light on why it needs to be set in a new variable? The same digit check used in the primary check on $1 just won't work for me but this does.

if ($_ =~ /\something(.*)somethingelse/i){ 
    if (($1 >= 1) and ($1 <= 75)) { 
        $a = $1;
        if ($a =~ /^\d+$/){ ... }
    }
}
[download]

You weren't doing the check on $1 in your original code.

if($1 => 1 and $1 <= 75 and /\d{1}-\d{2}/) { ... }
[download]

The /\d{1}-\d{2}/ is done on $_, not $1.

BTW you could just do the whole-number check right away:

if ($_ =~ /\something(\d*)somethingelse/i){ 
    if($1 => 1 and $1 <= 75) { ... }
}
[download]

Is 70.00 ok?

If so, I'd suggest a simple and $1 == int($1)

Sadly no, I only want it to accept a whole number and no decimals; if they entered 20.00 i'd wait it to fail to no.

C:\>perl -E "my $num ='abcd23.5fghi';if ($num =~ /[a-z]+(.*?)[a-z]/i){
+ say $1;}"
23.5                                                      /^\
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C:\>perl -E "my $num ='abcd23.5fghi';if ($num =~ /[a-z]+(.*)[a-z]/i){ 
+say $1;}"
23.5fgh    # not what OP seems to want
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C:\>perl -E "my $num ='abcd23fghi'; my $intermediate; if ($num =~ /[a-
+d]+(\d+)[f-z]+/) {$intermediate = $1;} if ($intermediate =~ /[0-9]+/ 
+){ say $intermediate;}"
23
[download]

C:\>perl -E "my $num ='abcd23.777fghi'; my $intermediate; if ($num =~ 
+/[a-d]+(\d+)[f-z]+/) {$intermediate = $1;} if ($intermediate =~ /[0-9
+]+/ ){ say $intermediate;}"
(no output)
[download]

The previous discussion should make it easy to identify the cause of the failure.

use 5.012;

my $num = 2;

if ($num => 2) {
    say 'yes';
}

$num = 1;

if ($num => 2) {
    say 'yes';
}

--output:--
yes
yes
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my %hash = (
    'a' => 2,
    'b' => 3,
    'c' => 4,
);

use Data::Dumper;
say Dumper(\%hash);

--output:--
$VAR1 = {
          'c' => 4,
          'a' => 2,
          'b' => 3
        };
[download]

Match only valid patterns.

/known string([1-6]?\d|7[0-5])another known string/
[download]

Also rather than the clumsy /\d{1}-\d{2}/ you might wish to use /[0-9]+/

Of course, those regexes don't match the same things:

use strict;
use warnings;
use 5.012;

my $str = "8-91";

if ($str =~ /(\d{1}-\d{2})/) {
    say $1;
}
if ($str =~ /([0-9]+)/) {
    say $1;
}

--output:--
8-91
8
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