在PHP中循环的条件语句中向数组添加元素

Question

I have this piece of code:

while ($i = $res->fetchArray(SQLITE3_ASSOC))
{
    $items[] = $i;
}

I tried neatening it to this:

while ($items[] = $res->fetchArray(SQLITE3_ASSOC));

It looks very satisfying but I now get an extra element at the end of the array (when the call to fetchArray() returns false. Is there a way of writing this statement without getting the extra element at the end?

Answer 1

If you're using PDO as your database library, you should use the fetchAll() method ( documentation )

$items = $stmt->fetchAll(PDO::FETCH_ASSOC)

This will provide you a bidimensional associative array. Its index goes from 0 to n-1 where n is the fetched rows count and every row contains an array with column names as indexes. For example:

$items[3]['id']

will contain the value stored in the id column of the 4th fetched row.

if you're using mysqli_* instead, there is mysqli_fetch_all() but it's discouraged because it's more expensive rather a loop of mysqli_fetch_array(), or so the documentation says.

If you're using a third party library, consult the provided documentation. If there is none provided or there is no fetchAll equivalent it's a sign of poor quality. Drop it and use the native PDO instead.

Since you're using SQLITE3 driver, i suggest you to look at this page: SQLITE (PDO) which explains how to use PDO with SQLITE3. Believe me, it's worth it. Most probably you won't stick to SQLITE for long and when you'll migrate to MySQL or PostgreSQL you'll thank me for this read.

PDO's main advantage is that's (usually) transparent to the user regarding which DB is below. Therefore, it shouldn't break your application if you change database, just change the PDO connection string and it'll be enough.

Answer 2

尝试

while(($item=$res->fetchArray(SQLITE3_ASSOC))&&$items[]=$item);