<?php
 
function is_sequential (array $array, bool $strict = false) {
    return array_filter($array, "is_int", ARRAY_FILTER_USE_KEY) == ($strict ? $array : true);
}
 
$array = ["foo", "baz", "bar"];
 
if (is_sequential($array, true)) {
    for ($i = 0; $i < count($array); $i++) {
        echo $array[$i], PHP_EOL;
    }
}
 
$array = ["foo", "baz" => "bar"];
 
if (is_sequential($array, true)) {
    for ($i = 0; $i < count($array); $i++) {
        echo $array[$i], PHP_EOL;
    }
}

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