How to avoid re-comparison of strings in following scenario? - php

Question

My PHP code snippet is as follows:
$sql = " SELECT * FROM ".TBL_QUESTIONS." WHERE question_subject_id=".$subject_id;
$sql .= " AND question_topic_id=".$topic_id;
$this->mDb->Query($sql);
$questions_data = $this->mDb->FetchArray();
$questions = $questions_data;
$exclude_words = array('which','who','what','how','when','whom','wherever','the');
/*This loop removes all the words of $exclude_words array from all questions*/
foreach($questions as $index=>$arr) {
$questions_array = explode(' ',$arr['question_text']);
$clean_questions = array_diff($questions_array, $exclude_words);
$questions[$index]['question_text'] = implode(' ',$clean_questions );
}
/*Now the actual comparison of each question with every other question stats here*/
foreach ($questions as $index=>$outer_data) {
$questions_data[$index]['similar_questions_ids_and_percentage'] = Array();
$outer_question = $outer_data['question_text'];
$qpcnt = 0;
foreach ($questions as $inner_data) {
/*This is to avoid comparing the question with itself*/
if ($outer_data['question_id'] != $inner_data['question_id']) {
$inner_question = $inner_data['question_text'];
/*This is to calculate percentage of match between each question with every other question*/
/*In this loop I want single time comparison of each question with every other question Now it's getting repeated, please help me here*/
$same_chars = similar_text($outer_question, $inner_question, $percent);
$percentage = number_format((float)$percent, 2, '.', '');
/*If $percentage is >= $percent_match only then push the respective question_id into an array*/
if($percentage >= 50) {
$questions_data[$index]['similar_questions_ids_and_percentage'][$qpcnt]['question_id'] = $inner_data['question_id'];
$questions_data[$index]['similar_questions_ids_and_percentage'][$qpcnt]['percentage'] = $percentage;
$qpcnt++;
}
}
}
}
Actually I want to avoid the re-comparison in a inner foreach loop from above code.
For example suppose there are ten questions and each one is comparing with other all remaining questions. If Q. No.1 is compared with Q. No. 8 then again when the time comes for Q.8, it's getting compared with Q.1 again. I want to avoid this. I want that if Q.1 is compared with Q.8 then again it should not be compared with Q. No.1 when the turn for Q. 8 comes.
Can anyone please help me out in this regard? any kind of help would be hoghly appreciated.

Answer 1

Maybe you can update the second foreach to also get the index:
foreach ($questions as $inner_data) {
changed to:
foreach ($questions as $secondIndex=>$inner_data){
and just under it add:
if ($secondIndex <= $index)
continue;