...which is populated through a loop and if statements

 So I have some data: 
 
>hsa_circ_0075116|chr5:175956288-175956388-|NM_014901|RNF44  FORWARD
-4.6      12 ..      35   xxxxGTGTGTGGTCT          GC TTCAGTGACTTCGAGG
+CGCG GC           AGCTGCTCCGAGTCC
-5.5      11 ..      36   xxxxxGTGTGTGGTC         TGC TTCAGTGACTTCGAGG
+CGCG GCA          GCTGCTCCGAGTCCT
-7.8      10 ..      37   xxxxxxGTGTGTGGT        CTGC TTCAGTGACTTCGAGG
+CGCG GCAG         CTGCTCCGAGTCCTC
-4.3       9 ..      38   xxxxxxxGTGTGTGG       TCTGC TTCAGTGACTTCGAGG
+CGCG GCAGC        TGCTCCGAGTCCTCC
-4.6      31 ..      41   CAGTGACTTCGAGGC                 GCGG CAG CTG
+C                 TCCGAGTCCTCCCCT
-5.7      28 ..      44   CTTCAGTGACTTCGA              GGCGCGG CAG CTG
+CTCC              GAGTCCTCCCCTGCA
-5.1      20 ..      49   GTGGTCTGCTTCAGT       GACTT CGAGGCGCGGCAGCTG
+CTCC GAGTC        CTCCCCTGCAACCAT
-4.3      27 ..      56   GCTTCAGTGACTTCG       AGGCG CGGCAGCTGCTCCGAG
+TCCT CCCCT        GCAACCATGAGTTCC
-5.6      31 ..      58   CAGTGACTTCGAGGC        GCGG CAGCTGCTCCGAGTCC
+TCCC CTGC         AACCATGAGTTCCAC
-5.4      72 ..      82   GCAACCATGAGTTCC                 ACAC CAA GTG
+T                 GTTGACAAGTGGTTG
-7.7      71 ..      83   TGCAACCATGAGTTC                CACAC CAA GTG
+TG                TTGACAAGTGGTTGA
-4.2      70 ..      84   CTGCAACCATGAGTT               CCACAC CAA GTG
+TGT               TGACAAGTGGTTGAA
>hsa_circ_0014931|chr1:160293220-160293320-|NM_001098398|COPA  FORWARD
-5.5      11 ..      36   xxxxxGGTCACGATC         GTG GAGTAAACTGGGCTGC
+CTTC CAC          CCCACTATGCCCCTT
-4.5      22 ..      40   GATCGTGGAGTAAAC             TGGGCTG CCTTC CA
+CCCCA             CTATGCCCCTTATTG
-4.1      11 ..      41   xxxxxGGTCACGATC      GTGGAG TAAACTGGGCTGCCTT
+CCAC C-CCAC       TATGCCCCTTATTGT

[download]

And I want to create a hash which has the name of the sequence 'hsa_circ...' as the key and the hash itself will be an array, containing a series of 'starts' and 'ends' which are chosen after going through some conditional if statements.

For example with respect to hsa_circ_0075116|chr5:175956288-175956388-|NM_014901|RNF44 FORWARD I want to capture this as the hash key. But then as I read the file in line by line I want to ask if statements regarding the start and end position values and then push them into the array of their respective hash.

So my problem is twofold:

(1) I want to be able to create a hash of arrays that is added to as the file is read

(2) I want to be able to read in line by line asking if statements of whether the start value and end value is within a positional vicinity of 6 such that it is essentially 1 hairpin and in which case I push into my array the start and end values which have the greatest range.

For example in: 
-4.6      <b>12 ..      35</b>   xxxxGTGTGTGGTCT          GC TTCAGTGAC
+TTCGAGGCGCG GC           AGCTGCTCCGAGTCC
-5.5      <b>11 ..      36</b>   xxxxxGTGTGTGGTC         TGC TTCAGTGAC
+TTCGAGGCGCG GCA          GCTGCTCCGAGTCCT
-7.8      <b>10 ..      37</b>   xxxxxxGTGTGTGGT        CTGC TTCAGTGAC
+TTCGAGGCGCG GCAG         CTGCTCCGAGTCCTC
-4.3       <b>9 ..      38</b>   xxxxxxxGTGTGTGG       TCTGC TTCAGTGAC
+TTCGAGGCGCG GCAGC        TGCTCCGAGTCCTCC
-4.6      31 ..      41   CAGTGACTTCGAGGC                 GCGG CAG CTG
+C                 TCCGAGTCCTCCCCT

[download]
The start positions and end positions surrounded by bold tags are essentially the same hairpin, so all except 9 and 38 will be ignored since it is this one that captures the hairpin best.

I am struggling to programmatically articulate these if statements though. Essentially I am trying to read each line capturing the values and assessing whether the next line bears values which are $start-1 and $end+1 and if they are, then they become the $start and $end and this is repeated until -/+6 of the orginal $start and $end value is reached

Trying to populate the hash of arrays: 
#!/usr/bin/perl 
use strict;
use warnings;

open my $hairpin_file, '<', "test.hairpin", or die $!;

my %HoA_sequences;

while (my $line = <$hairpin_file>){
    if ($line =~ /^>hsa/){
        $HoA_sequences{$line} = 
## Do I provide the key for the hash as soon as I read in the line bea
+ring the sequence name?
## And can I create a hash with a key but no hash? I'm guessing not. :
+/
    }

}

[download]
Trying to develop the if statements: 


if ($line =~ /$RE{num}{real}\s+($RE{num}{real})\s..+($RE{num}{real})+/
+){
    my $start = $1 && my $end = $2;
## Once captured how do I continue to the next line to query if the 
## value is - or + of the start and end values
}

[download]

In reply to Making use of a hash of an array... by Peter Keystrokes

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