php codeigniter数据库查询

Question

i want to answer like this

["Badin","Bahawalnagar","Bahawalpur"]

but when i run query

if ($result->num_rows() > 0)
    {   
        echo '[';
        foreach($result->result() as $listing)
        {
            echo '"'.$listing->city_name.'"';
            if ($listing->city_name!='')
            {
                echo ',';
            }
        }
        echo ']';
    }

then i got an extra coma in the last plz help me out to remove this

i want remove last coma ["Badin","Bahawalnagar","Bahawalpur",]

Answer 1

You code should look like this:

if ($result->num_rows() > 0)
{   
    echo '[';

    foreach($result->result() as $key => $listing)
    {
        $row = $key+1;

        if ($listing->city_name != '')
        {
            echo '"'.$listing->city_name.'"';

            // If it's not last item, then add a comma
            if ($row < $result->num_rows())
            {
                echo ',';
            }
        }
    }
    echo ']';
}

I assumed also, that you don't want to echo the city name if it's empty, otherwise you'd end up with empty "" .

Answer 2

Your output suspiciously similar to json, maybe a straight json_encode() is enough once you get the city names:

$cities = array();
foreach($result->result() as $listing) {
   $cities = $listing->city_name;
}
$cities = array_values(array_filter($cities)); // removes the empty ones, reset the indexes


echo json_encode($cities);

Also, you could use implode() for concatenation like this too:

echo '["'.implode('","', $cities).'"]';

Answer 3

You can use json_encode to do this

if($result->num_rows > 0){
  foreach ($result->result_array() as $row){


    $new_row['label']=htmlentities(stripslashes($row['user_name']));
     $new_row['val']=htmlentities(stripslashes($row['user_id']));

    $row_set[] = $new_row; //build an array
  }
  echo json_encode($row_set); //format the array into json data
}

Answer 4

you can concat your results into a variable and trim rightmost ",".

if ($result->num_rows() > 0)
    {   
    $my_result = '';
        echo '[';
        foreach($result->result() as $listing)
        {
            $my_result .=  '"'.$listing->city_name.'"';
            if ($listing->city_name!='')
            {
                $my_result .= ',';
            }
        }

    $my_result = rtrim($my_result , ",");

    echo $my_result;
        echo ']';
    }