How to convert time format into numbers in php

In PHP, date and time data are usually represented as text strings. These strings simply describe the date or time and do not convert the date or time into a number. But in some cases, we may need to convert date or time strings into numbers for easy comparison or calculation. This article will explain how to convert common time formats to numbers in PHP.

1. Unix timestamp

Unix timestamp is a number that represents the number of seconds that have elapsed since January 1, 1970. In PHP, you can use the time() function to get the Unix timestamp of the current time. For example, the following code will output the Unix timestamp of the current time:

echo time();

The output may look like: 1616031159

You can use the strtotime() function to convert any date string to a Unix timestamp. For example, the following code will output the Unix timestamp corresponding to 21:45 on March 18, 2021:

echo strtotime("2021-03-18 21:45:00");

The output may be similar to: 1616097900

2. YYYYMMDDHHIISS format

Another way to convert dates and times to numbers is to use the YYYYMMDDHHIISS format. This format compresses the date and time into a 14-digit numeric string. Among them, the first 8 digits represent the date (year YYYY, month MM, date DD), and the last 6 digits represent the time (hour HH, minute II, second SS). For example, 14:30:15 on March 15, 2021 can be expressed as 20210315143015.

You can use the strtotime() function to convert the date string into YYYYMMDDHHIISS format. For example, the following code will output the numeric string corresponding to 21:45 on March 18, 2021:

echo date("YmdHis", strtotime("2021-03-18 21:45:00"));

The output result may be similar to: 20210318214500

You can use the strtotime() function to After converting any date and time string to a UNIX timestamp, use the date() function to convert the UNIX timestamp to YYYYMMDDHHIISS format. For example, the following code will output the numeric string corresponding to 21:45 on March 18, 2021:

echo date("YmdHis", strtotime("2021-03-18 21:45:00"));

The output result may be similar to: 20210318214500

3. YYYY format

Sometimes, we just need to use the year to represent the date or time. In this case, use the YYYY format to compress the date or time string into a 4-digit number. For example, the year 2021 can be expressed as 2021.

You can use the date() function to convert date or time to YYYY format. For example, the following code will output the numeric string of the current year:

echo date("Y");

The output may look like: 2021

4. Week number

In some Sometimes we may need to use week numbers to represent dates or times. PHP has a built-in function for calculating the week number of a date. The function is:

int date('W', int $timestamp);

The $timestamp parameter can be a Unix timestamp or any date and time string that supports the strtotime() function. This function will return the week number of the specified date. For example, the following code will output the week number of March 18, 2021:

echo date("W", strtotime("2021-03-18"));

The output result may be similar to: 11

Using the above method, you can easily combine various common Convert time formats to numbers for comparison, calculation, and sorting operations in your PHP applications.

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