การใช้ตัวแปรในสตริง (String Interpolation)

$sql = "SELECT * FROM table";
$sql .= "WHERE id = '" . $id . "'";

$sql = "UPDATE table SET name = '" . $name . "', color = '" . $color . "'";
$sql .= "type = '" . $type . "' WHERE id = '" . $id . "'";

$a = "Hello World $str";
$b = "Hello World " . $str; // เร็วกว่า

$a = "Hello World $str !!!";
$b = "Hello World " . $str . " !!!"; // แต่แบบนี้ไม่

$sql = "UPDATE table SET name = '" . $name . "', color = '" . $color . "'";
$sql .= ", type = '" . $type . "' WHERE id = '" . $id . "'";

$fastSQL = "UPDATE table SET name = '$name', color = '$color', type = '$type' WHERE id = '$id'"; // แบบนี้เร็วกว่ามาก

$sql = "INSERT INTO table";
$sql .= "(first_name, last_name, username, password)";
$sql .= "VALUES ('" . $first_name . "','" . $last_name . "'"
$sql .= ",'" . $username . "','" . $password . "')";

$sql = "
    INSERT INTO table
    (first_name, last_name, username, password)
    VALUES
    ('$first_name','$last_name','$username','$password')
";

echo "Test $item[0]['name']";

echo "Test $item['name']";

Parse error: syntax error, unexpected T_ENCAPSED_AND_WHITESPACE

$id = $_POST['id'];
$name = $_POST['name'];
$address = $_POST['address'];
$sql = "INSERT INTO users VALUES ('$id', '$name', '$address')";

$sql = "INSERT INTO users VALUES ('$_POST[id]', '$_POST[name]', '$_POST[address]')";

$a = 123;
$b = 456;
$c = 789;

echo "a = $a, b = $b, c = $c\n";

echo <<<DOC
a = $a
b = $b
c = $c
DOC;

$a = 555;
echo "a is $a.";

$a = array(123, 456, 789);
echo "สมาชิกตัวแรกของ a คือ $a[0] ตัวที่ 2 คือ $a[1] และสุดท้ายคือ $a[2]";

$a = array(123, 456, 789);
echo "สมาชิกตัวแรกของ a คือ $a[0] ตัวที่ 2 คือ $a[1.0] และสุดท้ายคือ $a[2.0]";
// Parse error: syntax error, unexpected '.'

$ages = array('david' => 45, 'sally' => 20, 'john' => 31);
echo "David is $ages[david] years old\n";
echo "Sally is $ages[sally] years old\n";
echo "John is $ages[john] years old\n";

$stages = array('Level 1' => 'Forest');

echo "Welcome to stage 1 $stages[Level 1] !!!"; // Parse error: syntax error, unexpected T_ENCAPSED_AND_WHITESPACE

$users = array(

    array(
        'name' => 'Jack',
        'MAC address' => '01:23:45:67:89:AB',
    ),
    array(

        'name' => 'Mike',
        'MAC address' => '51:47:DF:EE:4C:13',
    ),

);

echo "User 1: {$users[0]['name']} - {$users[0]['MAC address']}\n";
echo "User 2: {$users[1]['name']} - {$users[1]['MAC address']}\n";

$users = array(

    array(
        'name' => 'Jack',
        'MAC address' => '01:23:45:67:89:AB',
    ),
    array(

        'name' => 'Mike',
        'MAC address' => '51:47:DF:EE:4C:13',
    ),

);

// แบบเชื่อมต่อสตริง
echo "User 2: " . $users[0.5 + 0.5]['name'] . " - " . $users[floor(0.3)]['MAC' . ' address'] . "\n";

// แบบนี้ไม่ต้องเปิดปิดสตริงให้เสียเวลา ลดความความเสี่ยงที่จะเกิดความผิดพลาดด้วย
echo "User 2: {$users[0.5 + 0.5]['name']} - {$users[floor(0.3)]['MAC' . ' address']}\n";