Gambaran Keseluruhan Jenis Data PHP

<?php
$single = 'Hello World';     // single — no variable parsing
$name   = 'PHP';
$double = "Hello $name";     // double — variables are interpolated

echo $double; // Hello PHP
echo strlen($single); // 11

<?php
$count  = 42;         // int
$neg    = -7;         // negative int
$hex    = 0x1A;       // hexadecimal = 26
$price  = 19.99;      // float
$sci    = 1.5e3;      // scientific = 1500.0

echo PHP_INT_MAX;   // largest integer on this platform
echo PHP_FLOAT_MAX; // largest float

<?php
$isActive = true;
$isDone   = false;

if ($isActive) {
    echo 'Active';   // runs
}

var_dump((bool) '');   // bool(false)
var_dump((bool) 'hi'); // bool(true)

<?php
$nothing = null;

var_dump(is_null($nothing));   // bool(true)
var_dump($nothing === null);   // bool(true)
var_dump($nothing == false);   // bool(true) — loose comparison

<?php
$mixed = [42, 'hello', true, null];
$map   = ['name' => 'Alice', 'age' => 30];

echo gettype($mixed);        // array
echo count($mixed);          // 4
echo $map['name'];           // Alice

<?php
$val = 3.14;

var_dump(is_int($val));    // bool(false)
var_dump(is_float($val));  // bool(true)
var_dump(is_string($val)); // bool(false)
var_dump(is_numeric('42')); // bool(true) — string that looks like a number

<?php
declare(strict_types=1);

function add(int $a, int $b): int {
    return $a + $b;
}

echo add(3, 4);    // 7
// add(3, '4');   // TypeError in strict mode!

<?php
function greet(string $name): string {
    return 'Hello, ' . $name . '!';
}

function divide(float $a, float $b): ?float {
    if ($b === 0.0) return null;  // nullable return
    return $a / $b;
}

echo greet('PHP');          // Hello, PHP!
var_dump(divide(10, 0));    // NULL

<?php
// fopen returns a resource
$handle = fopen('data.txt', 'r');

echo gettype($handle); // resource

fclose($handle); // always free resources when done

<?php
declare(strict_types=1);

function format(int|float $number): string {
    return number_format($number, 2);
}

echo format(1234);     // 1,234.00
echo format(9.5);      // 9.50