QUESTION 1 / 15 · TYPES & COMPARISONMedium
What does this print in PHP 8?
var_dump(0 == "a");
What this PHP test measures, in short
This test checks whether you can predict what modern PHP does: how == juggles types, when arrays are copied, how references and closures capture variables, how objects and static calls behave, and what PHP 8 features like match, enums, readonly and ?-> do.
Snippets assume PHP 8.3 with the opening <?php tag left out. The questions are our own and not standardised against a population, so treat the result as a knowledge check, not a certification.
By What's Your IQ · Reviewed 4 Oct 2026- Format
- 15 predict-the-output questions, 4 options each
- Topics
- Types and comparison, strings and arrays, functions and closures, OOP, modern PHP
- Version
- PHP 8.3
- Language
- Created by Rasmus Lerdorf, 1994
QUESTIONS 1 TO 3, ALL AT ONCE
Which of these are equal?
0"0"""nullfalse"a"[]
0"0"""nullfalse"a"[]
0 == "a"false"a" isn't numeric, so since PHP 8 the int is converted to a string and they're compared as strings. Before PHP 8 this was the other way round.Click any square. With == there are 16 equal pairs out of 49; with === only the 7 on the diagonal.
PHP 5 HABITS → PHP 8
Not the PHP you remember
OLD HABIT
$id = $_GET["id"];$r = mysqli_query($db, "SELECT * FROM users WHERE id = $id");
MODERN
$stmt = $pdo->prepare( "SELECT * FROM users WHERE id = ?");$stmt->execute([$_GET["id"]]);$user = $stmt->fetch();
Building SQL from request input invites SQL injection. Prepared statements send the value separately from the query, so it can never be run as SQL.
~3 in 4websites with a known server language use PHPW3Techs has reported a share around three-quarters for years, helped by WordPress, which runs on PHP.3
1994 → 1995Personal Home Page Tools. Rasmus Lerdorf wrote a set of CGI scripts to track visits to his online CV, then released them publicly.1
2015 · 7.0Twice as fast. The rewritten engine roughly doubled real-world performance over PHP 5.6 and added scalar type declarations.2
2020 · 8.0Saner comparisons. 0 == "a" became false, alongside match, named arguments, the nullsafe operator and a JIT compiler.2
2021 · 8.1Enums and readonly. Native enums, readonly properties and fibers brought PHP's type system closer to other modern languages.2
- The PHP Group. History of PHP. php.net manual.
- The PHP Group. PHP 7.0, 8.0 and 8.1 release announcements. php.net.
- W3Techs. Usage statistics of server-side programming languages for websites.