PHP date and time application 11: three methods to compare two specified dates

In the previous article "PHP Date and Time Application Ten: Convert Seconds to the Format of "Days, Hours, Minutes and Seconds"", I introduced to you how to convert seconds to the format of "Days, Hours, Minutes and Seconds" ”, then this article continues the PHP date and time series of articles~

As the title states, the main content of this article is to introduce to you three methods of comparing two specified dates!

Suppose we are given two dates (date1 and date2). When the formats of the two dates are the same, it is very simple to compare the two dates in PHP, but when the formats of the two dates are different Some problems will arise.

→Related recommendations: "Summary of PHP date and time usage (continuously updated~)"

So today you can master these three methods of comparing dates:

The first method: If the given date formats are the same, use simple comparison operations symbol to compare dates.

The code is as follows:

<?php


//声明两个日期、初始化
$date1 = "2021-11-24";
$date2 = "2001-03-26";

// 使用比较运算符比较日期
if ($date1 > $date2)
    echo "$date1 比 $date2 晚";
else
    echo "$date1 比 $date2 早";

Output result:

2021-11-24 比 2001-03-26 晚

Second method: If two given dates If the format is different, use the strtotime() function to convert the given date into the corresponding timestamp format, and finally compare these numeric timestamps to obtain the desired result.

The code is as follows:

<?php


// 声明两个不同的日期格式
$date1 = "12-03-26";
$date2 = "2011-10-24";

// 使用strtotime()函数进行转换
$dateTimestamp1 = strtotime($date1);
$dateTimestamp2 = strtotime($date2);

// 比较时间戳日期
if ($dateTimestamp1 > $dateTimestamp2)
    echo "$date1 比 $date2 晚";
else
    echo "$date1 比 $date2 早";

Output result:

12-03-26 比 2011-10-24 晚

The third method: Use the DateTime class Compare two dates .

The code is as follows:

<?php

//声明两个不同的日期

//格式化并使用DateTime()函数

//将日期转换为DateTime
$date1 = new DateTime("20-11-24");
$date2 = new DateTime("2021-03-26");

// 比较的日期
if ($date1 > $date2)
    echo $date1->format("Y-m-d") . " 比 "
        . $date2->format("Y-m-d")." 晚 ";
else
    echo $date1->format("Y-m-d") . " 比 "
        . $date2->format("Y-m-d")." 早 ";

The output result is:

2020-11-24 比 2021-03-26 早

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