php - 到达最后一行时如何回显不同的内容？

Question

我不想回显最后一行后回显末尾的逗号。我怎样才能做到这一点？这是我的代码:

<?php
    header("Content-type: application/json");
    echo '{"points":[';

    mysql_connect("localhost", "user", "password");
    mysql_select_db("database");

    $q = "SELECT venues.id, venues.lat, venues.lon, heat_indexes.temperature FROM venues, heat_indexes WHERE venues.id = heat_indexes.venue_id";

    $res = mysql_query($q) or die(mysql_error());
    while ($point = mysql_fetch_assoc($res)) {
    echo $point['lat'] . "," . $point['lon'] . "," . $point['temperature'] . ",";
    }
    mysql_free_result($res);
    echo ']}';
    ?>

Answer 1

你能不能用json_encode()相反，而不是手工制作 JSON？

$result = array();

//snip

while ($point = mysql_fetch_assoc($res)) {
    $result[] = $point['lat'];
    $result[] = $point['lon'];
    $result[] = $point['temperature'];
}

//snip

header("Content-type: application/json");
echo json_encode( array('points' => $result) );