Analyze this PHP code and explain the memory implications. What are the potential issues and how would you optimize it?

Code Analysis:

function processLargeDataset($filename) {
    $data = file_get_contents($filename); // 100MB file
    $lines = explode("\n", $data);
    $results = [];
    
    foreach($lines as $line) {
        $processed = expensive_operation($line);
        $results[] = $processed;
    }
    
    return $results;
}

Memory Issues:

• Memory Spike: file_get_contents() loads entire file into memory
• Double Memory Usage: explode() creates another copy of data
• Array Growth: $results array grows continuously
• Peak Usage: Could reach 300MB+ for 100MB file

Optimized Solution:

function processLargeDatasetOptimized($filename): Generator {
    $handle = fopen($filename, "r");
    if (!$handle) throw new Exception("Cannot open file");
    
    try {
        while (($line = fgets($handle)) !== false) {
            yield expensive_operation(trim($line));
        }
    } finally {
        fclose($handle);
    }
}

// Usage with memory control
foreach(processLargeDatasetOptimized($filename) as $result) {
    // Process one result at a time
    // Memory usage remains constant
}

Benefits: Constant memory usage, lazy evaluation, better performance for large datasets.