Comparing DB rows?

burstroo

Say, for example, I have one row.. that looks like.

1372903478947385689346598346563489563498563
4573405734095834905834905803495834907590347
5345439573490753490753490750934750937590347
5435349057349057349073094839084903284093284

I will try and compare that with the other rows in the database. This is actually a form algorythm that these numbers are converted from. (Each number has something to do with a word that is found in the algorythm, but again I cannot say anything about that - it was give the whole concept up.) -

So, what I will be doing is:

Take Database Row 1:

1372903478947385689346598346563489563498563
4573405734095834905834905803495834907590347
5345439573490753490753490750934750937590347
5435349057349057349073094839084903284093284

Compare it with Database Row 2:

1372903478947349058349058034958349038568934
6598346563489563498563457340573409587590347
5345439573490753490753490750934750937590347
543534905734905734907309483908490328 you4093284

As will see, it looks a lot the same - but it's 'not'. I want to see how many #'s in a row are the same, and I want to keep a running total throughout the search. Like here's 1+1+1+1+1+1+1+1+1+1+1+1 in a row.. oh wait there's a different one.. dont count it.. .. keep adding along with out total 1+1+1+1+1+1+1+1.. ope, there's another not the same..aaaannd back to normal 1+1+1+1+1.

So throughout that count we got..25 numbers that matched up according to my standards. I kept a running total of consecutives.

If it helps you out, I'll do this in coke, pepsi, and dew so you can understand the #'s.

#1
c,p,d,d,c,d,c,c,p,p,p,p,p,p,a,a,a,a

#2
c,p,c,c,c,d,c,c,p,d,d,a,a,c,c,a,a,a,a

Now if you do the comparison:

1 2

c c .. That's one
p p .. Another one
d c .. Not one,... so our count is still two
d c .. Not one...our count is still two
c c .. There is one - it's a count of three
d d .. there's our fourth
c c .. a 5th
c c .. 6th
p p .. 7th
p d .. NO! .. we stil only have 7
p d .. still no
p a .. nope
p a .. no
p c ..no
a c ..no
a a .. 8TH!!!
a a ..9th
a a ..10th

So, out of 18 comparisons, we only got a total of 10 run consecutives. Later on, I will devide this number and get a percentage of match.. and in this case it's like 55% match. But I'm not worried about the percentage yet.

Any clue how to compare it like so?

samudasu

This script will compare characters between two strings. It strips out newlines and carriage returns incase your strings span multiple lines. If the two strings are different lengths you'll get error messages so you'll want add some checking code if you plan to do that. You can easily convert this into a function.

<?php
$stra = '1372903478947385689346598346563489563498563';
$strb = '1372903478947349058349058034958349038568934';

$clean = array("\n", "\r");
$stra = str_replace($clean, "", $stra);
$strb = str_replace($clean, "", $strb);
$counter = 0;
$strlen = strlen($stra);
for ($i = 0; $i < $strlen; $i++) {
    if($stra{$i} == $strb{$i}) {
        $counter++;
        print "Character $i : " . $stra{$i} . " " . $strb{$i} . "\n";
    }
}
print "$counter characters match out of $strlen total";
?>