unable to change input data and db query result to array for pattern recognition

Question

I'm unable to change an input string($prima = $_POST['id'];) and a db query result ($systemuser['id'];) into an array which will be used for pattern matching using one single character at a time and then trying to find a match in the database "id" row that is queried. The point is to use two-third of an id(supposedly incomplete id of a user of a system) to query and find the complete id. Please see my code. I'd appreciate some help. Thanks I'm getting "undefined offset:0 through 9" error.

<?php
session_start();
include_once('server.php');

$error = false;
$gat = "";
$get = "";
$rt1 = "";
$rt2 = "";
$rt3 = "";
$rt4 = "";
$rt5 = "";
$rt6 = "";
$rt7 = "";
$rt8 = "";
$rt9 = "";
$rt0 = "";


if(isset($_POST['btn-login'])){

$firstname = $_POST['firstname'];
$firstname = trim($firstname);
$firstname = trim($_POST['firstname']);
$firstname = htmlspecialchars(strip_tags($firstname));  

$lastname = $_POST['lastname'];
$lastname = trim($lastname);
$lastname = trim($_POST['lastname']);
$lastname = htmlspecialchars(strip_tags($lastname));

$id = $_POST['id'];
$id = trim($id);
$id = trim($_POST['id']);
$id = htmlspecialchars(strip_tags($id));

$gender = $_POST['gender'];


   if(!$error) {
    //search data if no errors 

    $query = "select * from subscribers";
    $conditions = array();

    if(! empty($firstname)){
        $conditions[] = "firstname='$firstname'";
    }

    if(! empty($lastname)){
        $conditions[] = "lastname='$lastname'";
    }

    if(! empty($gender)){
        $conditions[] = "gender='$gender'";
    }


   $sql = $query;
    if(count($conditions) > 0){
        $sql .= " WHERE " . implode(' AND ', $conditions);
    }


    $result = mysqli_query($conn, $sql);


    while($systemuser = mysqli_fetch_array($result, MYSQLI_ASSOC)){

      $systemuser['id'];
      $gat = $systemuser['id'];

    }       


  //convert user input to array
    $prima = $_POST['id'];
    $prima = array();
    $rt1 = $prima[0];
    $rt2 = $prima[1];
    $rt3 = $prima[2];
    $rt4 = $prima[3];
    $rt5 = $prima[4];
    $rt6 = $prima[5];
    $rt7 = $prima[6];
    $rt8 = $prima[7];
    $rt9 = $prima[8];
    $rt0 = $prima[9];

    //retrieve and convert db data into array
    $gat = array(); 




    foreach( $gat as $get ){ 

    $rt1 = $prima[0];      
    if (preg_match("/[$rt1]+/", $gat));{
        $get += 1;
     }

    $rt2 = $prima[1];       
    if (preg_match("/[$rt2]+/", $gat)){ 
        $get += 1;
    }

    $rt3 = $prima[2];
    if (preg_match("/[$rt3]+/", $gat)){ 
        $get += 1;
    }

    $rt4 = $prima[3];
    if (preg_match("/[$rt4]+/", $gat)){ 
        $get += 1;
    }

    $rt5 = $prima[4];
    if (preg_match("/[$rt5]+/", $gat)){ 
        $get += 1;
    }

    $rt6 = $prima[5];
    if (preg_match("/[$rt6]+/", $gat)){ 
        $get += 1;
    }

    $rt7 = $prima[6];
    if (preg_match("/[$rt7]+/", $gat)){ 
        $get += 1;
    }

    $rt8 = $prima[7];
    if (preg_match("/[$rt8]+/", $gat)){ 
        $get += 1;
    }

    $rt9 = $prima[8];
    if (preg_match("/[$rt9]+/", $gat)){
        $get += 1;
    }

    $rt0 = $prima[9];
    if (preg_match("/[$rt0]+/", $gat)){ 
        $get += 1;
    }

    if ($get > 9){
        echo 'match found!';

    }
    else{
        echo 'match not found!';
    }


    }




   }

}

?>

Is someone just pulling our leg today with these? PHP flog instead of golf? — ficuscr
– ficuscr, Commented Jul 18, 2018 at 22:40
Why do you feel it necessary to do things 2 or 3 times instead of once — RiggsFolly
– RiggsFolly, Commented Jul 18, 2018 at 22:47
Some sensible code indentation would be a good idea. It helps us read the code and more importantly it will help you debug your code Take a quick look at a coding standard for your own benefit. You may be asked to amend this code in a few weeks/months and you will thank me in the end. — RiggsFolly
– RiggsFolly, Commented Jul 18, 2018 at 22:47

ficuscr · Accepted Answer · 2018-07-18 23:11:20Z

0

I started to refactor but there is just too much that is wrong.

You are getting that Undefined offset: 0 notice because...

<?php
$prima = array();
$rt1 = $prima[0];

Is referencing offset zero on an empty array. The code makes no sense. You seem to frequently assign a value and then overwrite in on the next line.

FWIW: strings in PHP can behave much like an array...

UPDATE:

I'm a little confused about crux here honestly. If I wanted to reference the first and second letters in a string I would do:

$str = "I like PHP";
$firstLetter = (isset($str[0])) ? $str[0] : '';
$secondLetter = (isset($str[1])) ? $str[1] : '';

See if you can follow this example:

$str = 'I like PHP';
for ($i=0; $i<strlen($str); $i++) {
    echo $str[$i] . "|"; 
}

And then... are you looking to do a WHERE foo LIKE 'a%' type query? A "wildcard" search?

edited Jul 18, 2018 at 23:11

answered Jul 18, 2018 at 22:55

ficuscr

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5 Comments

ficuscr Over a year ago

It's fine, and evident :) We were all rookies when we started. Try and view other peoples code, PHP frameworks for example, learn from them, github is a great resource for that. An IDE would also probably help you out a lot - catch things like assigning a value to a variable that you never go on to reference.

harrid Over a year ago

Ok I get you. but how do I change an input data into an array containing values? I'm trying to separate the characters of input data and get them to standalone. same with that from the db?

harrid Over a year ago

Thanks for the corrections... your second code, looks like a loop to me. Do you mind clarifying a bit. The user input string in my program has no spaces. Its more like a username. e.g... jacksonfive as against yours I love PHP

harrid Over a year ago

Yes referencing the letters in string and trying to find a match from the queried db data result $systemuser['id']. If two-third of the characters of the string are contained in any of the returned set of IDs( $systemuser['id']), then there's a match.

ficuscr Over a year ago

You probably just need to look at function like strstr. Sorry, have to run. Maybe look at an existing implementation of autocomplete?

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