Boostrap 4 Flexbox行是否以列显示，而不是以行显示？

Question

我有以下代码，根据我发现的示例，它看起来应该将它们写在水平行中，但实际上它被呈现为列？

<div class="d-flex">
    <div class="flex-row">
        <div class="p-2">January</div>
        <div class="p-2">February</div>
        <div class="p-2">March</div>
        <div class="p-2">April</div>
    </div>
    <div class="flex-row">
        <div class="p-2">May</div>
        <div class="p-2">June</div>
        <div class="p-2">July</div>
        <div class="p-2">August</div>
    </div>
    <div class="flex-row">
        <div class="p-2">September</div>
        <div class="p-2">October</div>
        <div class="p-2">November</div>
        <div class="p-2">December</div>
    </div>
</div>

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​

Answer 1

“弹性框行是否以列而不是行的形式显示？”

因为flex-row不是display:flex。flex-row应与d-flex位于同一元素中

<div>
    <div class="d-flex flex-row">
            <div class="p-2">January</div>
            <div class="p-2">February</div>
            <div class="p-2">March</div>
            <div class="p-2">April</div>
    </div>
    <div class="d-flex flex-row">
            <div class="p-2">May</div>
            <div class="p-2">June</div>
            <div class="p-2">July</div>
            <div class="p-2">August</div>
    </div>
    <div class="d-flex flex-row">
            <div class="p-2">September</div>
            <div class="p-2">October</div>
            <div class="p-2">November</div>
            <div class="p-2">December</div>
    </div>
</div>

https://www.codeply.com/go/HnEbrelWCC