PHP has an enormous standard library of string functions, inconsistent naming conventions and all — a working knowledge of the common ones saves constant trips to the documentation.
str_contains("Hello World", "World"); // true (PHP 8+)
str_starts_with("Hello", "He"); // true
str_pad("7", 3, "0", STR_PAD_LEFT); // "007"
substr("Hello World", 0, 5); // "Hello"
str_replace("World", "PHP", "Hello World"); // "Hello PHP"
trim(" padded "); // "padded"
explode(",", "a,b,c"); // ['a', 'b', 'c']
implode(", ", ['a', 'b', 'c']); // "a, b, c"
sprintf("%05.2f", 3.14159); // "03.14"
wordwrap("A long sentence here", 10, "\n", true);
ucwords("hello world"); // "Hello World"
PHP 8’s str_contains(), str_starts_with(), and str_ends_with() replaced the old, error-prone pattern of checking strpos() !== false — worth updating older code to use them for readability alone.