When should you use an empty array in a web application? : <p>I'm learning Ruby and several tutorials introduce empty arrays and pushing values in them.</p>

<p>I googled "When are empty arrays used?" and there seems to be no web pages that talk about practical empty array usage.</p>

<p>My assumption is that empty arrays are used when arrays elements are unknown and external input provides the array elements. But I cannot think of any examples...</p>
