What potential issues can arise when using foreach loops in PHP, especially when dealing with multiple data sets?

When using foreach loops in PHP with multiple data sets, a potential issue that can arise is variable contamination. This occurs when variables used within the loop are not properly scoped, leading to unexpected behavior or errors. To solve this, you can use the `unset()` function to clear the loop variable after each iteration, ensuring that it does not affect subsequent iterations or data sets. 

$dataSets = [
    [1, 2, 3],
    ['a', 'b', 'c'],
];

foreach ($dataSets as $dataSet) {
    foreach ($dataSet as $value) {
        echo $value . ' ';
    }
    
    unset($value); // Clear the loop variable
    echo PHP_EOL;
}

Keywords

foreach loops PHP multiple data sets array iteration

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