Breakdown of script :-
// We need to know how many rows there are in the '$rows' array,
// so we can loop through each one looking at all of the values,
// which is held in $max_rows
$max_rows = count($rows);
// Firstly, we loop around every instance of $rows, using 'foreach'.
// The key to the $rows array, i.e. 0, 1, 2, 3, etc is loaded into
// $array_key and the value is loaded in $array_value.
//
// Remember that $array_value is an array itself, but PHP
// is quite happy with this as it is a 'loosely typed' language, so
// you can load any type of value into any variable
//
// There are 2 loops going on in the code, one to take us through each
// row as a main loop, and another to go back through all the rows at the
// time, comparing the row to all of the other rows
//
// If we were to look inside the loops, we would see something like this :-
//
// MAIN LOOP SUB-LOOP
// current row -> compare to
// 0 1
// 0 2
// 0 3
// 1 0
// 1 2
// 1 3
// 2 0
// 2 1
// 2 3
// 3 0
// 3 1
// 3 2
//
// Notice that we never compare the current row to itself, we simply
// step over it
//
foreach ($rows as $array_key => $array_value) {
// lets output a message to say which array row we're currently
working on
// We know which one it is, because we loaded that information in
// $array_key, i.e. 0, 1, 2, etc
echo "<br>Curr row = " . $array_key . " - <br>\n";
// Now the good bit
// We have to loop round all of the rows (in $rows) independently of
the loop
// we're doing in our 'foreach' above, but we must not compare the
row to
// inself
//
// First of all, we set a counter, called $i, to zero
// We keep looping round until we get to the end of the rows, by
looking at
// the value of $max_rows
for ($i = 0; $i < $max_rows; $i++) {
// In this statement we check to see if the row we're
currently
// checking in our 'for' loop, is the same row as the row
we're on
// in our 'foreach' loop. Remember, we must not compare a row
to itself
if ($array_key <> $i) {
// Compare the elements in $array_value, which holds
the current
// $rows array to the current $rows in our 'for'
loop, and store the results
// in $common
$common = array_intersect($array_value, $rows[$i]);
// Loop round each of the matching values, in
$common, and output them
foreach ($common as $key => $value) {
echo "Key: $key; Value: $value\n";
}
echo "<BR>";
}
}
}
-----Original Message-----
From: php-objects@xxxxxxxxxxxxxxx [mailto:php-objects@xxxxxxxxxxxxxxx] On
Behalf Of Robert Barker
Sent: 17 January 2008 18:11
To: php-objects@xxxxxxxxxxxxxxx
Subject: RE: HOW DO I CREATE A LOOP CRAWLER?
EXCELLENT WORK ROB. THANK YOU VERY MUCH.
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