PHP Time Comparisons: A Detailed Guide

Comparing times in PHP can be a tricky task to master. This article will provide a comprehensive explanation of how to effectively compare times using various methods.

Current Solution's Limitation

The code snippet provided in the question, where you attempt to compare $NowisTime with $ThatTime, fails because the comparison is between strings. PHP's string comparison does not account for time differences properly.

Solution Using Time Stamps

One reliable approach is to convert both times into time stamps using mktime() or strtotime() and then perform a numerical comparison. The following revised code demonstrates this:

$ThatTime = "14:08:10";
if (time() >= strtotime($ThatTime)) {
  echo "ok";
}

In this case, time() returns the current time stamp, and strtotime() converts $ThatTime into a time stamp. The comparison is now straightforward and accurate.

Solution Using DateTime (with Timezone Awareness)

PHP's DateTime class allows for more sophisticated time comparisons that account for time zones. Here's how you can utilize it:

$dateTime = new DateTime($ThatTime);
if ($dateTime->diff(new DateTime)->format('%R') == ' ') {
  echo "OK";
}

The diff() method calculates the difference between two DateTime objects, and the format() method returns it in a specific format, such as '%R' here to indicate a positive or negative difference.