打印数组键和值

Question

Given a table called "people" where names of people are associated to their city, I need to retrieve the number of people who come from the same city.

PEOPLE      CITY
John        Baltimore
David       London
Paula       Baltimore
Mark        Baltimore
Alex        London

My code is as follows:

$array_cities = array();
$query = "SELECT * FROM people";
$result = mysql_query($query);
if ($result) {
    while ($record = mysql_fetch_array($result))
    $array_cities[] = $record['city'];
}
print_r(array_count_values($array_cities));

And what I get in my browser is:

Array ( [Baltimore] => 3 [London] => 2 )

The output is correct, but it is not graphically good. What I would want is something like:

Baltimore => 3 London => 2

Are there any other options to get it?

Answer 1

That's just the output from print_r() . If you want something else, just loop through the array an print it:

foreach(array_count_values($array_cities) as $k => $v)
   echo $k . " => " . $v . " ";

---

Sidenote:

Besides print_r() there are also var_dump() and var_export() , which are all "debugging functions". So use them for debugging and not for printing "nice formatted output".

Answer 2

You need to use the MySQL function COUNT(*) & the GROUP BY clause:

$array_cities = array();
$query = 'SELECT COUNT(*) AS `persons`, `city` FROM `people` GROUP BY `city`';
$result = mysql_query($query);
if ($result) {
    while ($record = mysql_fetch_array($result)) {
        $array_cities[$record['city']] = $record['persons'];
    }
}
print_r($array_cities);