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capitalize

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​

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"