bootstrap align vertical a code example

Example 1: bootstrap vertical align

<div class="d-flex align-items-start">...</div>
<div class="d-flex align-items-end">...</div>
<div class="d-flex align-items-center">...</div>
<div class="d-flex align-items-baseline">...</div>
<div class="d-flex align-items-stretch">...</div>

Example 2: how to center vertically in bootstrap col

<div class="my-auto">
  ...inner divs and content...
</div>