Strings

Single vs double quotes

Double-quoted strings interpolate variables. Single-quoted strings are mostly literal.

<?php
$name = "Ada";
echo 'Hello $name\n';
echo "Hello $name\n";

Concatenate

Use the . operator to join strings.

echo "Hi, " . $name . "!\n";

Useful functions

PHP provides many string helpers.

$raw = "  php  ";
echo trim($raw), "\n";
echo strtoupper("php"), "\n";
echo strlen("php"), "\n";

String habits

• Prefer single quotes when you do not need interpolation
• Be careful with user input and HTML escaping (htmlspecialchars)
• Multibyte text may need mb_* functions
• Heredoc/nowdoc help with multi-line templates