String comparison with alternate character variables - php

Question

Right to the problem...user need to input text (to be specific the input text is serial number), this input must be compared with database. However because of small print user will make mistake between characters like: (B/8), (1/l),(0,o),(u,v).
The question is how to make the user input "l234B" a valid entry when the serial number is "12348"??
here is another examples: o12u3 ---> 012v3
thanks.

Answer 1

Some solution might be to replace all occorences like "8" by "[8B]" to match against both possibilities:
$sn = "l234B"; $sn_new = "";
$problematic_chars = ['B' => 'B8', '8' => 'B8', '1' => '1l', 'l' => '1l', ...];
// Go through original string and create new string
// "l234B" becomes "[1l]234[8B]"
for($i = 0; $i < strlen($sn); $i++) {
$char = $sn[$i];
if (array_key_exists($char, $problematic_chars)) {
$sn_new .= "[".$problematic_chars[$char]."]";
} else {
$sn_new .= $char;
}
}
// Query stuff
$sql = "SELECT * FROM table_name WHERE sn REGEXP '^${sn_new}\$'";
Did not write PHP for long time, but I think you get the idea.

Answer 2

You may want to try similar_text function rather than using regular expressions and validate only non-ambiguous chars.

Answer 3

// to query
$id = "ABF8...";
// all combinations pre-generated
$c = array(
array('B' => 'B', '8' => '8', ...),
array('B' => 'B', '8' => 'B', ...),
array('B' => '8', '8' => '8', ...),
array('B' => '8', '8' => 'B', ...),
...
);
// generating all versions
foreach($c as $v)
{
$ids[] = strtr($id, $v);
}
the optimal solution depends on your specific setup. but probably you will have the IDs somewhere and you have to query them. so you will have to replace the ambigiuous chars in all possible combinations and query those.
strtr()