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@ 2024-09-24T19:13:12Z

<?php

function chained(iterable ...$input): Generator
{
    foreach ($input as $iterable) {
        yield from $iterable;
    }
}

echo "The \"chained\" elements using a generator: ";
foreach(chained(
    [1,2,3],
    [4,5],
) as $item){
    echo "$item ";
}
echo "\n\n";

echo "However, when it comes to converting the generator to array, there is a caveat:\n";

$numbers = chained(
    [1,2,3],
    [4,5],
);
print_r(
    iterator_to_array($numbers)
);

echo "\n";
echo "The issue is caused by overlapping keys. See how they appear in the sequence:\n";

foreach(chained(
    [1,2,3],
    [4,5],
) as $key => $item){
    echo "[$key] => $item\n";
}
echo "\n\n";

echo "The issue is not present when the keys do not overlap:\n";

$numbers = chained(
    [1,2,3],
    [10 => 4,5],
);
print_r(
    iterator_to_array($numbers)
);

Output for git.master_jit, git.master: The "chained" elements using a generator: 1 2 3 4 5 However, when it comes to converting the generator to array, there is a caveat: Array ( [0] => 4 [1] => 5 [2] => 3 ) The issue is caused by overlapping keys. See how they appear in the sequence: [0] => 1 [1] => 2 [2] => 3 [0] => 4 [1] => 5 The issue is not present when the keys do not overlap: Array ( [0] => 1 [1] => 2 [2] => 3 [10] => 4 [11] => 5 )

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2020-03-21 RFC: Is_Literal - declined
2020-12-04 Enumerations - included in PHP 8.1
2018-06-15 Typed Properties v2 - implemented in PHP 7.4
2016-08-12 Object typehint - included in PHP 7.2
2016-08-14 Arrow functions - withdrawn
2016-05-29 array_change_keys() - withdrawn
2016-04-19 Lexical scope support for anonymous classes - suspended
2016-04-17 Functional Interfaces - declined
2016-03-16 Typed Properties - superseded in favor of Typed Properties 2.0
2015-08-27 Callable Prototypes - declined
2015-05-01 Short Closures - declined / withdrawn in favor of Arrow Functions
2015-02-18 Scalar type hints v5 - included in PHP 7
2015-02-14 Union Types - declined
2013-09-22 Anonymous classes - included in PHP 7

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