The SplFixedArray class

    (PHP 5 >= 5.3.0, PHP 7, PHP 8)

    Introduction

    The SplFixedArray class provides the main functionalities of array. The main difference between a SplFixedArray and a normal PHP array is that the SplFixedArray must be resized manually and allows only integers within the range as indexes. The advantage is that it uses less memory than a standard array.

    Class synopsis

    classSplFixedArrayimplementsIteratorAggregate, ArrayAccess, Countable, JsonSerializable {
    public__construct(int$size = 0)
    publiccount(): int
    publiccurrent(): mixed
    publicstaticfromArray(array$array, bool$preserveKeys = true): SplFixedArray
    publicgetIterator(): Iterator
    publicgetSize(): int
    publicjsonSerialize(): array
    publickey(): int
    publicnext(): void
    publicoffsetExists(int$index): bool
    publicoffsetGet(int$index): mixed
    publicoffsetSet(int$index, mixed$value): void
    publicoffsetUnset(int$index): void
    publicrewind(): void
    public__serialize(): array
    publicsetSize(int$size): bool
    publictoArray(): array
    public__unserialize(array$data): void
    publicvalid(): bool
    public__wakeup(): void
    }

    Changelog

    VersionDescription
    8.2.0 The SplFixedArray::__serialize() and SplFixedArray::__unserialize() magic methods have been added to SplFixedArray.
    8.1.0SplFixedArray implements JsonSerializable now.
    8.0.0SplFixedArray implements IteratorAggregate now. Previously, Iterator was implemented instead.

    Examples

    Example #1 SplFixedArray usage example

    <?php
    // Initialize the array with a fixed length
    $array = new SplFixedArray(5);

    $array[1] = 2;
    $array[4] = "foo";

    var_dump($array[0]); // NULL
    var_dump($array[1]); // int(2)

    var_dump($array["4"]); // string(3) "foo"

    // Increase the size of the array to 10
    $array->setSize(10);

    $array[9] = "asdf";

    // Shrink the array to a size of 2
    $array->setSize(2);

    // The following lines throw a RuntimeException: Index invalid or out of range
    try {
    var_dump($array["non-numeric"]);
    } catch(    RuntimeException $re) {
    echo     "RuntimeException: ".$re->getMessage()."\n";
    }

    try {
    var_dump($array[-1]);
    } catch(    RuntimeException $re) {
    echo     "RuntimeException: ".$re->getMessage()."\n";
    }

    try {
    var_dump($array[5]);
    } catch(    RuntimeException $re) {
    echo     "RuntimeException: ".$re->getMessage()."\n";
    }
    ?>

    The above example will output:

     NULL int(2) string(3) "foo" RuntimeException: Index invalid or out of range RuntimeException: Index invalid or out of range RuntimeException: Index invalid or out of range

    Table of Contents

    To Top