How does a PHP function return a traverser?

PHP functions can return traversers by using the yield keyword, which generate values ​​one by one, thereby saving memory, improving code readability, and supporting other usages such as filters, converters, and aggregators.

How the PHP function returns a traverser

A traverser is a lazy data structure that generates values ​​one by one as needed, thus Avoid the memory consumption caused by generating the entire collection at once. Functions in PHP can return traversers by using the yield keyword.

Syntax:

function* generatorName(): Generator
{
    // 生成值
    yield $value1;
    // ...
}

Practical example:

Consider a function that returns a iterator of a range of numbers.

function numberRange(int $start, int $end): Generator
{
    for ($i = $start; $i <= $end; $i++) {
        yield $i;
    }
}

Use this traverser:

foreach (numberRange(1, 10) as $number) {
    echo "$number ";  // 输出：1 2 3 4 5 6 7 8 9 10
}

Advantages:

• Memory efficiency: The traverser only generates requests value, thus saving memory.
• Deferred Execution: Traversers can delay certain operations until they are needed.
• Code readability: Using traversers can make the code more readable and maintainable.

Other uses:

• Filter: Filter elements from a dataset.
• Converter: Convert elements in a dataset.
• Aggregator: Perform aggregation operations on data sets.

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