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resize

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.

Resize the current Vector

public function resize(
  int $size,
  Tv $value,
): void;

Resize the current Vector to contain $sz elements. If $sz is smaller than the current size of the current Vector, elements are removed from the end of the current Vector. If $sz is greater than the current size of the current Vector, the current Vector is extended by appending as many copies of $value as needed to reach a size of $sz elements.

$value can be null.

If $sz is less than zero, an exception is thrown.

Parameters​

  • int $size
  • Tv $value - The value to use as the filler if we are increasing the size of the current Vector.

Returns​

  • void

Examples​

This example shows how resize can be used to decrease and increase the size of a Vector:

$v = Vector {'red', 'green', 'blue', 'yellow'};

// Resize the Vector to 2 (removing 'blue' and 'yellow')
$v->resize(2, null);
\var_dump($v);

// Resize the Vector back to 4 (filling in 'unknown' for new elements)
$v->resize(4, 'unknown');
\var_dump($v);