Capitalize

:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::

Returns the string with the first character capitalized

namespace HH\Lib\Str;

function capitalize(
  string $string,
): string;

If the first character is already capitalized or isn't alphabetic, the string will be unchanged.

• To capitalize all characters, see Str\uppercase().
• To capitalize all words, see Str\capitalize_words().

Guide

• String

Parameters

• string $string

Returns

• string

Examples

$result = Str\capitalize("example_string");
echo($result);
// result "Example_string"

$result = Str\capitalize("Example_string");
echo($result);
// result "Example_string"