典雅的检查，如果给定的日期是昨天

问题描述：

假设你有一个Unix时间戳，这将是一件容易的和/或优雅的方式来检查，如果该时间戳是一段时间昨天？

Assuming you have a Unix timestamp, what would be an easy and/or elegant way to check if that timestamp was some time yesterday?

我主要是找在Javascript，PHP或C＃，但伪代码和语言无关的解决方案（如果有的话），欢迎为好。

I am mostly looking for solutions in Javascript, PHP or C#, but pseudo code and language agnostic solutions (if any) are welcome as well.

答

PHP解决方案

$isYesterday = date('Ymd', $timestamp) == date('Ymd', strtotime('yesterday'));