PHP String Functions

What You’ll Find Here

PHP ships with dozens of built-in string functions for escaping text, splitting CSV data, joining tags, encoding HTML, and converting binary formats. This page is your central hub: browse every function in our tutorial series, jump to full guides with examples and output, and learn patterns that work in real PHP programs.

Introduction

In PHP, strings are one of the most common data types. You work with them using global functions such as explode(), htmlspecialchars(), and implode()—not dot notation like Python. These functions make everyday tasks fast and readable: cleaning user input, building comma-separated lists, escaping HTML for safe output, and converting data between hex and binary.

🚀 Usage Tips

• Escape HTML output — always use htmlspecialchars($text, ENT_QUOTES, "UTF-8") before echoing user data in HTML.
• Split and join pairs — use explode() to parse CSV or tag lists, then implode() to rebuild them.
• Know your encoding — HTML entity functions default to ISO-8859-1; pass "UTF-8" explicitly for modern apps.
• Prefer prepared statements — never rely on addslashes() alone for SQL; use PDO or MySQLi prepared statements.
• Check return types — some functions return false on failure (e.g. hex2bin() with invalid hex); always validate before use.
• Read the tutorial — each linked function page includes syntax, five examples, a quick reference table, and FAQs.

📝 How to Call a String Function

Every PHP string function follows the same general pattern:

function_name($string, ...optional_args)

Common Patterns

Functions vs Object Methods

If you come from Python or JavaScript, remember: PHP string helpers are functions, not methods on a string object. You write strlen($name), not $name.length or $name->strlen(). The string is passed as an argument, and the function returns the result.

<?php
$raw = "  Hello, World!  ";
$clean = trim($raw);                    // remove whitespace
$parts = explode(",", $clean);          // split into array
$joined = implode(" + ", $parts);       // join back together
$safe = htmlspecialchars($joined, ENT_QUOTES, "UTF-8");
echo $safe;
?>