Format String

<?php
// Contoh 1: format angka dan uang
$harga = 1500000;
echo number_format($harga);                 // "1.500.000" (format Indonesia otomatis)
echo number_format($harga, 2, ",", ".");    // "1.500.000,00": 2 desimal

$diskon = 0.157;
echo number_format($diskon * 100, 1) . "%";  // "15,7%": persen rapi

// Contoh 2: sprintf untuk template presisi
$nama = "Sinta";
$skor = 92;
echo sprintf("Halo %s, nilaimu %d.", $nama, $skor);
// "Halo Sinta, nilaimu 92.": %s = string, %d = integer

<?php
// Contoh 2 lanjutan: struk belanja dengan kolom sejajar
$items = [
    ["Kopi", 2, 15000],
    ["Roti Bakar Coklat", 1, 12000],
];

foreach ($items as [$nama, $qty, $harga]) {
    $subtotal = $qty * $harga;
    // %-20s: rata kiri lebar 20; %10s: rata kanan lebar 10
    echo sprintf("%-20s %3d x %10s = %10s\n",
        $nama, $qty,
        number_format($harga),
        number_format($subtotal));
}
// Kopi                 2 x     15.000 =     30.000
// Roti Bakar Coklat    1 x     12.000 =     12.000

<?php
$total = number_format(1500000);   // "1.500.000" (STRING!)
$bayar = $total + 50000;           // 1 + 50000 = 50001?! Titik dianggap juggling aneh

<?php
echo number_format(1500000);                // 1.500.000 (Indonesia)
echo number_format(1500000, 2, ",", ".");   // 1.500.000,00
echo number_format(1500000, 2, ".", ",");   // 1,500,000.00 (Amerika)

// Helper rupiah sekali tulis, pakai selamanya
function rupiah(float $angka): string {
    return "Rp" . number_format($angka, 0, ",", ".");
}
echo rupiah(1500000);   // Rp1.500.000

// Hati-hati: jangan format dua kali!
$h = rupiah(15000);          // "Rp15.000" (string!)
echo rupiah((float) str_replace(["Rp", "."], "", $h));  // ribet! hindari