How to convert date to number of days in php

In PHP development, it is often necessary to convert dates into days for date calculation and processing. In this article, we will introduce how to achieve date to number of days conversion in PHP using different functions.

1. Use timestamp to calculate the number of days

The timestamp refers to the number of seconds that have passed since 0:00:00 on January 1, 1970 to the present , usually used to handle dates and times. Therefore, we can use timestamp to calculate date to day conversion. The following is a sample code:

$date1 = strtotime("2021-10-01");
$date2 = strtotime("2021-10-10");
$diff = abs($date2 - $date1);
$days = floor($diff / (60*60*24));
echo "相差天数：$days";

This code first uses the strtotime function to convert the date string into a timestamp, then uses the abs function to calculate the time difference between the two dates, and uses the floor function to convert the time difference into Number of days.

2. Use DateTime to calculate the number of days

The DateTime class is a new date/time processing class added after PHP 5.2, which provides more convenient and flexible date processing functions. Dates can be converted directly into days using the DateTime class. The following is a sample code:

$date1 = new DateTime("2021-10-01");
$date2 = new DateTime("2021-10-10");
$diff = $date1->diff($date2);
$days = $diff->days;
echo "相差天数：$days";

This code first uses the DateTime class to create a date object, then uses the diff method to calculate the time difference between two dates, and uses the days attribute to convert the time difference into days.

3. Use the strtotime function to calculate the number of days from a specific date to today

Sometimes we need to calculate the number of days from a specific date to today. You can use the strtotime function in combination with time. function to implement. The following is a sample code:

$today = time();
$birthday = strtotime("1990-01-01");
$diff = $today - $birthday;
$days = floor($diff / (60*60*24));
echo "距离出生已有：$days 天";

This code first uses the time function to obtain the current timestamp, then uses the strtotime function to convert the birthday to a timestamp, calculates the time difference from the birth date to the current time, and finally uses the floor function to convert The time difference is converted to days.

Summary

In this article, we introduced the conversion method of using timestamp and DateTime class to calculate date to number of days, and how to use strtotime function to calculate specific The number of days from the date to today. Which method to choose can be chosen according to the specific situation, but no matter which method is used, you need to pay attention to the correctness of the time format and the calculation method of the time difference.

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