- 01Getting Started
- 02Your First Output (echo)
- 03Working with Variables
- 04Conditionals (if statements)
- 05Loops (for statements)
- 06Writing a Function
- 07Working with Arrays
- 08Loops (while statements)
- 09Classes (Object-Oriented Programming)
- 10Error Handling (try...catch)
- 11Handy Array Functions
- 12Recursive Functions
- 13Using the Standard Library
- 14The switch Statement
- 15The Ternary Operator
- 16Inheritance (Extending a Class)
- 17Writing Comments
- 18Logical Operators (AND, OR, NOT)
- 19Constants (define / const)
- 20Splitting and Joining Strings (explode, implode)
- 21Writing Null-Safe Code (the ?? operator)
- 22Searching an Array (in_array)
- 23Transforming an Array (array_map)
- 24Two-Dimensional Arrays (Tabular Data)
- 25Writing a Custom Exception Class
- 26Default Parameter Values
- 27Using an Array as a Set (Duplicate-Free Data)
- 28Checking Correctness (Your First Step into Testing)
- 29Higher-Order Functions (Passing a Function as an Argument)
- 30Stacks and Queues (Basic Data Structures)
- 31Type Conversion (Casting) Basics
- 32Intro to Regular Expressions (Pattern Matching)
- 33The Binary Search Algorithm
- 34Building a Caesar Cipher (a Character-Shifting Cipher)
- 35Understanding How Bubble Sort Works
- 36Building and Displaying Dates (Basic Year/Month/Day Operations)
- 37Writing Multiple Test Cases Together
- 38Speeding Up Calculations with Memoization (Caching)
- 39Normalizing Strings (trim, Unifying Case)
- 40Shallow Copy vs. Deep Copy
- 41Enum (Enumerated Types) Basics
- 42Flattening an Array
- 43Reversing a String and Checking for Palindromes
- 44Pairing Up Two Arrays (the zip operation)
- 45Rounding Numbers (floor, ceil, round)
- 46Multi-Line Strings (Heredoc)
- 47Functions That Return Multiple Values (Arrays and list())
- 48Finding the GCD and LCM (the Euclidean Algorithm)
- 49Formatting Numbers (Padding Digits, Decimal Places)
- 50Cleanup Logic with try/catch/finally
- 51Functions That Work with Any Type
- 52File Reading and Writing Basics
- 53Generating Random Numbers
- 54Bitwise Operators (AND, OR, XOR, shifts)
- 55Reading Command-Line Arguments
- 56Waiting for a Fixed Amount of Time (sleep)
- 57Watch Out for Floating-Point Rounding Errors
- 58Reading from Standard Input
- 59FizzBuzz (the Classic Practice Problem)
- 60Checking Whether a Number Is Prime
- 61Set Operations with Arrays (Union, Intersection, Difference)
- 62Converting Number Bases (Binary, Hex)
- 63Checking Balanced Parentheses (an Application of Stacks)
- 64Checking Whether Two Words Are Anagrams
- 65Checking Whether a Year Is a Leap Year
- 66Converting Temperature (Celsius to Fahrenheit)
- 67Prime Factorization
- 68[Applied] Build a Simple Inventory Management Tool
Your First Output (echo)
In this lesson you will learn the basic way to print output in PHP with echo, and get a feel for a language that runs on a web server. This is for anyone searching for "PHP echo how to use" or "PHP basic syntax".
PHP prints text to the screen with echo. Code always starts with the <?php tag. What sets PHP apart is that it runs on a web server and can be embedded directly in HTML. Since its arrival in 1994 it has powered a huge share of the world's websites, making it a defining language of web development.
The sample code writes a single line, echo "Hello, PHP!";, inside a <?php tag. Famous content management systems such as WordPress are built in PHP, so learning the basics that start with echo is a first step towards understanding those large systems too.
A common stumbling block for beginners is forgetting the opening <?php tag. Without it, the code is not recognised as PHP and gets printed to the screen as plain text. Missing the semicolon ; at the end of a line is another frequent slip.
In practice PHP runs on the server and sends the result to the browser as HTML, so the source is never visible to the client. That "runs server-side" property is one reason PHP has stayed in use in web development for so long.
๐งช This site can't compile or run PHP directly, so it checks on the spot whether what you typed matches the reference code (scoring happens entirely in your browser โ nothing is sent anywhere).