D:\> 1123881a.pl

         --- Ln 25 Printing keys and values for the HASHES, %F1 and %F2
                 ...and creating ARRAYS @F1combined and @F2combined.
brown => 1
all => 1
their => 1
country => 1
is => 1
fox => 1
aid => 1
while => 1
to => 2
time => 1
for => 1
Now => 1
spooon => 1
dog's => 1
of => 1
away => 1
and => 1
with => 1
over => 1
run => 1
the => 5
quick => 1
fork => 1
red => 1
come => 1
men => 1
good => 1
lazy => 1
jump => 1

         --- %F2, next: ---
brown => 1
all => 1
runs => 1
jumps => 1
their => 1
country => 1
back => 1
is => 1
fox => 1
aid => 1
time => 1
while => 1
to => 2
for => 1
spoon => 1
dog's => 1
of => 1
away => 1
now => 1
with => 1
the => 6
and => 1
over => 1
fork => 1
quick => 1
red => 1
come => 1
men => 1
lazy => 1
good => 1
                 $item_count: 30
# some output, similar to the following, has been deleted for the sake of brevity
# (even so, brevity is not present in abundance)
...
>> Ln 56    $i: 22   |spooon => 1|
         didn't match entry, |spooon => 1|

>> Ln 56    $i: 23   |the => 5|              # No allowance for variance in occurences, 5 in file1 and 6 in DATA
         found |the| in both arrays (files)  # Part of the loose spec; should this count for similarity or dis-similarity?

>> Ln 56    $i: 24   |their => 1|
         found |their| in both arrays (files)

>> Ln 56    $i: 25   |time => 1|
         found |time| in both arrays (files)

>> Ln 56    $i: 26   |to => 2|
         found |to| in both arrays (files)

...

Use of uninitialized value $entry in scalar chomp at D:\_Perl_\pl_test\1123881a.pl line 55, <DATA> line 1.
Use of uninitialized value $entry in concatenation (.) or string at D:\_Perl_\pl_test\1123881a.pl line 56, <DATA
>> Ln 56    $i: 29   ||
Use of uninitialized value $entry in pattern match (m//) at D:\_Perl_\pl_test\1123881a.pl line 57, <DATA> line 1

         $match_count: 27
         $mismatch: 2

         SLOPPY SPEC: (AMONG OTHER ISSUES) does not treat cases where the number of instances of a word in one file
         is different than the number of instances in the second file as a mismatch (eg. if the word is in both, though in differing quanties, it's treated as a match.
         No allowance made for use with arrays having different numbers of elements (variance produces 'uninitialised" warnings


         Here's one measure of SIMILARITY (using matchs/total elements evaled): 0.9

         Another uses the total of matches and mismatches as the divisor: 0.931034482758621

         Magnitude of DIS-similarty (using the ratio of mismatches/matches) : 0.0740740740740741

         By the same sloppy spec, but using mismatch/elements_in_first_array): 0.0689655172413793