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I am trying to build an array from a list of URL parameters to transact with a database. Basically I have several functions that do different things. (Insert, Update, etc) so depending on what it is specifically trying to do it may not need ALL columns in the database at all times.

So say I have these 5 potential parameters that might get passed: id,gr,bl,yw,re

If I am inserting a new row all 5 coulmns need some sort of value. If I am say updating the bl column then I only pass the id and bl parameters.

So I am doing this to build the query string(not actual code just example):

foreach($_GET as $key => $value) {
$key = strtolower($key);
if (preg_match($acceptedGETS,$key)) $$key = $value;
}

$table_col = array (
    'p_id' => $_GET['id'],
    'p_gr' => $_GET['gr'],
    'p_bl' => $_GET['bl'],
    'p_yw' => $_GET['yw'],
    'p_re' => $_GET['re']);

$vstring = implode(',' , $table_col);

Now this works perfectly, as long as ALL variable keys have a value (or not NULL). My question is, how can I build a string from an array, but exclude the keys that don't get passed values. Right now if keys are missing values I get this for example:

URL: http://www.mysite.com/myscript.php?id=4&re=9 would get me:

4,,,,9

when I need to just get 4,9

Thanks!

share|improve this question
 
Always escape your strings with mysql_real_escape_string() before adding them to a query, if you're not using prepared statements. –  rid Apr 16 '12 at 22:07
 
Hi, the actual code is using mysql_real_escape_string() I was just posting sample code here to illustrate what I was doing. –  Chris Apr 16 '12 at 22:11

3 Answers

up vote 0 down vote accepted

Use $get = array_filter($_GET) and it will get rid of empty or null values.

share|improve this answer
 
Title fixed - keys should have been values. Lost train of thought typing title. –  Chris Apr 16 '12 at 22:13
 
and what about data validation and getting rid of injected values? –  Nazariy Apr 16 '12 at 22:30
 
The question wasn't about data validation and sql injection. It was about removing empty values from an array. –  Rob Apr 16 '12 at 22:48
 
I already have validation and injection measures in place, I just didn't know how to remove the empty values. –  Chris Apr 16 '12 at 22:53
 
@Rob the question was about stripping empty keys from 5 potential parameters, your example does not guarantees that there will be maximum of 5 parameters. –  Nazariy Apr 16 '12 at 23:03
up vote 0 down vote

Try

$vstring = "";
$acceptedGETS = array("id", "gr", "bl", "yw", "re");
$values = array();
foreach ($_GET as $key => $value)
{
    $k = strtolower($key);
    if (!in_array($k, $acceptedGETS))
        continue;
    $values[$k] = $value;
}
$vstring = implode(",", $values);
share|improve this answer
up vote -1 down vote

Here is another way using just filter_input_array and set of filters

$args = array(
    'id'    => FILTER_VALIDATE_INT,//if it is an integer
    'gr'    => FILTER_SANITIZE_STRIPPED,//in case it is a string
    'bl'    => FILTER_SANITIZE_STRIPPED,
    'yw'    => FILTER_SANITIZE_STRIPPED,
    're'    => FILTER_SANITIZE_STRIPPED,
);

//Filter array values to avoid bad data if nothing found NULL returned
$myInputs = filter_input_array(INPUT_GET, $args);

//if it is an array join it with coma
if(is_array($myInputs))
    $myInputs = implode(',', $myInputs);
share|improve this answer

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