How to convert date in ymd format to timestamp in php

PHP is a very powerful programming language that is widely used in various fields such as website development and application development. In PHP development, date and time conversion is a common problem. Among them, converting date strings into timestamps is also a frequently required operation. One of the most common date formats is the year-month-day (ymd) format. This article will introduce how to convert a date string in ymd format into a timestamp.

1. What is a timestamp

Before introducing how to convert a date string in ymd format into a timestamp, we first understand the concept of timestamp. Timestamp (timestamp) is a special time format, which refers to the number of seconds since 0:00 on January 1, 1970 (also called the Unix epoch). In PHP, timestamps can be obtained using the time() function. For example, the following line of code can get the timestamp of the current time:

$timestamp = time();

2. Convert YMD format date string to timestamp

In PHP, you can use the strtotime() function to convert Convert date string to timestamp. For example, the following line of code can convert a common date string in ymd format into a timestamp:

$timestamp = strtotime('2019-12-31');

In the above code, the strtotime function accepts a date string parameter and converts it into a timestamp. If the date string to be converted contains time information, you can also specify the time information in the string, for example:

$timestamp = strtotime('2019-12-31 23:59:59');

In addition, if you want to convert the current time to a timestamp, you can also omit the strtotime function parameters. For example:

$timestamp = strtotime();

3. Date formatting in PHP

In PHP, you can use the date() function to format a timestamp or date string into a date string with a specific format. For example, the following line of code can format a timestamp into a date string in year-month-day (ymd) format:

$dateString = date('Y-m-d', $timestamp);

In the above code, the date function accepts two parameters, the first parameter is Date format string, the second parameter is the timestamp to be formatted. Among them, Y in the date format string represents the four-digit year, m represents the two-digit month, and d represents the two-digit date, separated by a horizontal bar in the middle.

If you want to format the current time into a date string in ymd format, you can also omit the $date parameter. For example:

$dateString = date('Y-m-d');

4. Summary

This article introduces how to convert a date string in ymd format into a timestamp, and introduces the basic usage of date formatting in PHP. In actual development, we can flexibly use the strtotime() and date() functions as needed to convert between date and time.

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