note 90224 modified in function.array-slice by danbrown

I was trying to find a good way to find the previous several and next several results from an array created in a MySQL query. I found that most MySQL solutions to this problem were complex. Here is a simple function that returns the previous and next rows from the array. <?php /* ** function array_surround by Jamon Holmgren of ClearSight Design ** Version 1.0 - 4/10/2009 ** Please direct comments and questions to my first name at symbol clearsightdesign.com ** ** Returns an array with only the $before and $after number of results ** This is set to work best with MySQL data results ** Use this to find the rows immediately before and after a particular row, as many as you want ** ** Example usage: ** $mysql_ar is an array of results from a MySQL query and the current id is $cur_id ** We want to get the row before this one and five rows afterward ** ** $near_rows = array_surround($mysql_ar, "id", $cur_id, 1, 5) ** ** Previous row is now $near_rows[-1] ** Current row is now $near_rows[0] ** Next row is $near_rows[1] ... etc ** If there is no previous row, $near_rows[-1] will not be set...test for it with is_array($near_rows[-1]) ** */ function array_surround($src_array, $field, $value, $before = 1, $after = 1) { if(is_array($src_array)) { // reset all the keys to 0 through whatever in case they aren't sequential $new_array = array_values($src_array); // now loop through and find the key in array that matches the criteria in $field and $value foreach($new_array as $k => $s) { if($s[$field] == $value) { // Found the one we wanted $ck = $k; // put the key in the $ck (current key) break; } } if(isset($ck)) { // Found it! $result_start = $ck - $before; // Set the start key $result_length = $before + 1 + $after; // Set the number of keys to return if($result_start < 0) { // Oops, start key is before first result $result_length = $result_length + $result_start; // Reduce the number of keys to return $result_start = 0; // Set the start key to the first result } $result_temp = array_slice($new_array, $result_start, $result_length); // Slice out the results we want // Now we have an array, but we want array[-$before] to array[$after] not 0 to whatever. foreach($result_temp as $rk => $rt) { // set all the keys to -$before to +$after $result[$result_start - $ck + $rk] = $rt; } return $result; } else { // didn't find it! return false; } } else { // They didn't send an array return false; } } ?> I hope you find this useful! I welcome constructive criticism or comments or of course praise ;) -- just e-mail me. - Jamon Holmgren --was-- EDIT: I posted this under prev() but figured it was better posted here, since it uses array_slice() and not prev(). - JH I was trying to find a good way to find the previous several and next several results from an array created in a MySQL query. I found that most MySQL solutions to this problem were complex. Here is a simple function that returns the previous and next rows from the array. Refer to http://www.clearsightdesign.com/webdesign-scripts-array_surround.php for the latest version. <?php /* ** function array_surround by Jamon Holmgren of ClearSight Design ** Version 1.0 - 4/10/2009 ** Please direct comments and questions to my first name at symbol clearsightdesign.com ** This function is released under the GPL - free for private or commercial use ** Please do not sell this script. ** Script homepage: http://www.clearsightdesign.com/webdesign-scripts-array_surround.php ** ** Returns an array with only the $before and $after number of results ** This is set to work best with MySQL data results ** Use this to find the rows immediately before and after a particular row, as many as you want ** ** Example usage: ** $mysql_ar is an array of results from a MySQL query and the current id is $cur_id ** We want to get the row before this one and five rows afterward ** ** $near_rows = array_surround($mysql_ar, "id", $cur_id, 1, 5) ** ** Previous row is now $near_rows[-1] ** Current row is now $near_rows[0] ** Next row is $near_rows[1] ... etc ** If there is no previous row, $near_rows[-1] will not be set...test for it with is_array($near_rows[-1]) ** */ function array_surround($src_array, $field, $value, $before = 1, $after = 1) { if(is_array($src_array)) { // reset all the keys to 0 through whatever in case they aren't sequential $new_array = array_values($src_array); // now loop through and find the key in array that matches the criteria in $field and $value foreach($new_array as $k => $s) { if($s[$field] == $value) { // Found the one we wanted $ck = $k; // put the key in the $ck (current key) break; } } if(isset($ck)) { // Found it! $result_start = $ck - $before; // Set the start key $result_length = $before + 1 + $after; // Set the number of keys to return if($result_start < 0) { // Oops, start key is before first result $result_length = $result_length + $result_start; // Reduce the number of keys to return $result_start = 0; // Set the start key to the first result } $result_temp = array_slice($new_array, $result_start, $result_length); // Slice out the results we want // Now we have an array, but we want array[-$before] to array[$after] not 0 to whatever. foreach($result_temp as $rk => $rt) { // set all the keys to -$before to +$after $result[$result_start - $ck + $rk] = $rt; } return $result; } else { // didn't find it! return false; } } else { // They didn't send an array return false; } } ?> I hope you find this useful! I welcome constructive criticism or comments or of course praise ;) -- just e-mail me. - Jamon Holmgren http://php.net/manual/en/function.array-slice.php