In PHP, the ucfirst() function is used to convert the first character of a string to uppercase, while leaving the rest of the string unchanged.

Syntax:

ucfirst(string $string): string

Example 1: Basic Usage

<?php
$string = "hello world!";
$capitalized = ucfirst($string);
echo $capitalized;  // Output: Hello world!
?>

In this example, the first letter of the string "hello world!" is converted to uppercase, resulting in "Hello world!".

Example 2: String with Multiple Words

<?php
$string = "hello world! welcome to php.";
$capitalized = ucfirst($string);
echo $capitalized;  // Output: Hello world! welcome to php.
?>

Notice that ucfirst() only changes the first letter of the string. The subsequent words remain the same.

Example 3: Non-Alphabetic First Character

<?php
$string = "123 apple";
$capitalized = ucfirst($string);
echo $capitalized;  // Output: 123 apple
?>

If the string starts with a non-alphabetic character (e.g., a number), ucfirst() does not alter the string.

Example 4: Using ucfirst() on a String with Special Characters

<?php
$string = "#hello world!";
$capitalized = ucfirst($string);
echo $capitalized;  // Output: #hello world!
?>

In this case, the # character is preserved, and only the first alphabetic character (h) is capitalized.

This function is handy when you want to make sure that the first letter of a string (such as a name or title) is uppercase, but you don't want to alter the rest of the string.