How to wrap (float) cards in bootstrap 4

Question

I am using bootstrap 4 beta.

I have a list of cards. I want them to be of fixed width, but the height will be variable depending on the content.

The number of cards can be from 1 to n.

The effect I want is for the cards to be be laid out from left to right until screen space runs out, then wrap to next line.

I have tried all the different options listed on the bootstrap 4 example page for cards, but they don't seem to wrap.

How can I achieve this?

The below example shows them 3 across, with a lot of space between them.

 <div class="card-columns">

        <div class="card" style="width: 18rem;">
            <img class="card-img-top" data-src="..." alt="Card image cap">
            <div class="card-block">
                <h4 class="card-title">Card title</h4>
                <p class="card-text">This is a longer card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.</p>
                <p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>
            </div>
        </div>
        <div class="card"style="width: 18rem;">
            <img class="card-img-top" data-src="..." alt="Card image cap">
            <div class="card-block">
                <h4 class="card-title">Card title</h4>
                <p class="card-text">This card has supporting text below as a natural lead-in to additional content.</p>
                <p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>
            </div>
        </div>
        <div class="card" style="width: 18rem;">
            <img class="card-img-top" data-src="..." alt="Card image cap">
            <div class="card-block">
                <h4 class="card-title">Card title</h4>
                <p class="card-text">This is a wider card with supporting text below as a natural lead-in to additional content. This card has even longer content than the first to show that equal height action.</p>
                <p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>
            </div>
        </div>
        <div class="card" style="width: 18rem;">
            <img class="card-img-top" data-src="..." alt="Card image cap">
            <div class="card-block">
                <h4 class="card-title">Card title</h4>
                <p class="card-text">This is a longer card with supporting text below as a natural lead-in to additional content. This content is a little bit longer.</p>
                <p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>
            </div>
        </div>
        <div class="card" style="width: 18rem;">
            <img class="card-img-top" data-src="..." alt="Card image cap">
            <div class="card-block">
                <h4 class="card-title">Card title</h4>
                <p class="card-text">This card has supporting text below as a natural lead-in to additional content.</p>
                <p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>
            </div>
        </div>
        <div class="card" style="width: 18rem;">
            <img class="card-img-top" data-src="..." alt="Card image cap">
            <div class="card-block">
                <h4 class="card-title">Card title</h4>
                <p class="card-text">This is a wider card with supporting text below as a natural lead-in to additional content. This card has even longer content than the first to show that equal height action.</p>
                <p class="card-text"><small class="text-muted">Last updated 3 mins ago</small></p>
            </div>
        </div>
    </div>

Answer 1

After working with this for some time, the floating solution I came up with was unsatisfactory as in some cases, there was a large amount of space below some cards.. After reviewing bootstrap 4 cards, I found a feature that does exactly what I wanted it to: "card-columns"

It lines up your cards into three columns, and re-arranges to one column when the screen size is small.

Bootstrap Docs on card-columns