Timestamp from date string php

Содержание

How to convert datetime in PHP to a Unix timestamp
Overview
Problems
Converting datetime strings to a Unix timestamp
The incorrect approach
The correct approach
What is the Unix timestamp?
Code explanation
date
Parameters
Return Values
Errors/Exceptions
Changelog
Examples
Notes
See Also
User Contributed Notes

How to convert datetime in PHP to a Unix timestamp

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Overview

While working with the MySQL database in PHP, we may need to record the time instance at which an event occurs. This instance can be stored as a table record. We can the instance as a table record by using the datetime or timestamp MySQL data types. The problem associated with this procedure is that it cannot display the date in a very human-friendly and easily-readable format.

We get the following from the datetime and timestamp MySQL table columns:

But we may want to display the date in the format shown in the image below:

This shot teaches us how to display a date in this format, as a PHP script.

Before we learn to display the date in the aforementioned format, let’s look at the problems associated with MySQL table timestamp columns.

Problems

The datetime from the table is a string.
It comes from the database table column of type timestamp , which usually presents datetime in the format 2021-11-17 13:02:18 .
This format is not a Unix timestamp. We’ll need to convert the format to a Unix timestamp in order to get the date in the format shown in image above.

Converting datetime strings to a Unix timestamp

A combination of two PHP functions, the strtotime() and the date() functions, will produce an output like the one shown in the image above.

The strtotime() function converts any given date string into a Unix timestamp. It only accepts the date string as a parameter.
The date() function outputs the current time, or the time relative to the provided timestamp (if any), in the specified format. It takes the format we wish to display the date in and the optional timestamp as its two parameters.

Now, we will delve into some code examples.

The incorrect approach

The code below is an incorrect way of trying to get the output we’ve shown above, which may be our first approach while trying out solutions to that problem for the first time.

The output is not what we want, and that is because we didn’t convert the timestamp into a proper Unix timestamp before passing it to the date() function.

$mytimestamp = '2021-11-17 13:02:18';
// $dating = intval($mytimestamp);
// echo $dating;
$converted = date('m d, Y',$mytimestamp);
echo $converted;
?>

of a specific value fetched from the database in the provided code,##

The correct approach

In this second code, we use the strtotime() function to convert the datetime string from a database table into a Unix timestamp. Then, with the help of the date() function, we set the timestamp to various date formats of our choice.

What is the Unix timestamp?

This is the number of seconds since the Unix epoch time (01-01-1970) .

For more tips on the PHP date() function, we can see this post.

Note: The escape character is used in the code snippet below to escape the words that are just used as text, so that they are not given special interpretation by the function.

Code explanation

In the code below, a datetime string, saved in the variable ＄d , is converted to a Unix timestamp with the strtotime() function. It is then saved to the variable ＄ad on line 5.

Note: To use the current date and time instead of a specific value fetched from the database in the provided code, comment out ＄d = ‘2021-11-17 13:02:18’; with // and uncomment ＄d = date(‘Y-m-d H:i:s’); in the provided code, it will assign the current datetime to the variable ＄d .

Источник

date

Returns a string formatted according to the given format string using the given integer timestamp (Unix timestamp) or the current time if no timestamp is given. In other words, timestamp is optional and defaults to the value of time() .

Unix timestamps do not handle timezones. Use the DateTimeImmutable class, and its DateTimeInterface::format() formatting method to format date/time information with a timezone attached.

Parameters

Note: date() will always generate 000000 as microseconds since it takes an int parameter, whereas DateTime::format() does support microseconds if DateTime was created with microseconds.

The optional timestamp parameter is an int Unix timestamp that defaults to the current local time if timestamp is omitted or null . In other words, it defaults to the value of time() .

Return Values

Returns a formatted date string.

Errors/Exceptions

Every call to a date/time function will generate a E_WARNING if the time zone is not valid. See also date_default_timezone_set()

Changelog

Version	Description
8.0.0	timestamp is nullable now.

Examples

Example #1 date() examples

// set the default timezone to use.
date_default_timezone_set ( ‘UTC’ );

// Prints something like: Monday
echo date ( «l» );

// Prints something like: Monday 8th of August 2005 03:12:46 PM
echo date ( ‘l jS \of F Y h:i:s A’ );

// Prints: July 1, 2000 is on a Saturday
echo «July 1, 2000 is on a » . date ( «l» , mktime ( 0 , 0 , 0 , 7 , 1 , 2000 ));

/* use the constants in the format parameter */
// prints something like: Wed, 25 Sep 2013 15:28:57 -0700
echo date ( DATE_RFC2822 );

// prints something like: 2000-07-01T00:00:00+00:00
echo date ( DATE_ATOM , mktime ( 0 , 0 , 0 , 7 , 1 , 2000 ));
?>

You can prevent a recognized character in the format string from being expanded by escaping it with a preceding backslash. If the character with a backslash is already a special sequence, you may need to also escape the backslash.

Example #2 Escaping characters in date()

It is possible to use date() and mktime() together to find dates in the future or the past.

Example #3 date() and mktime() example

$tomorrow = mktime ( 0 , 0 , 0 , date ( «m» ) , date ( «d» )+ 1 , date ( «Y» ));
$lastmonth = mktime ( 0 , 0 , 0 , date ( «m» )- 1 , date ( «d» ), date ( «Y» ));
$nextyear = mktime ( 0 , 0 , 0 , date ( «m» ), date ( «d» ), date ( «Y» )+ 1 );
?>

Note:

This can be more reliable than simply adding or subtracting the number of seconds in a day or month to a timestamp because of daylight saving time.

Some examples of date() formatting. Note that you should escape any other characters, as any which currently have a special meaning will produce undesirable results, and other characters may be assigned meaning in future PHP versions. When escaping, be sure to use single quotes to prevent characters like \n from becoming newlines.

Example #4 date() Formatting

// Assuming today is March 10th, 2001, 5:16:18 pm, and that we are in the
// Mountain Standard Time (MST) Time Zone

$today = date ( «F j, Y, g:i a» ); // March 10, 2001, 5:16 pm
$today = date ( «m.d.y» ); // 03.10.01
$today = date ( «j, n, Y» ); // 10, 3, 2001
$today = date ( «Ymd» ); // 20010310
$today = date ( ‘h-i-s, j-m-y, it is w Day’ ); // 05-16-18, 10-03-01, 1631 1618 6 Satpm01
$today = date ( ‘\i\t \i\s \t\h\e jS \d\a\y.’ ); // it is the 10th day.
$today = date ( «D M j G:i:s T Y» ); // Sat Mar 10 17:16:18 MST 2001
$today = date ( ‘H:m:s \m \i\s\ \m\o\n\t\h’ ); // 17:03:18 m is month
$today = date ( «H:i:s» ); // 17:16:18
$today = date ( «Y-m-d H:i:s» ); // 2001-03-10 17:16:18 (the MySQL DATETIME format)
?>

To format dates in other languages, IntlDateFormatter::format() can be used instead of date() .

Notes

Note:

To generate a timestamp from a string representation of the date, you may be able to use strtotime() . Additionally, some databases have functions to convert their date formats into timestamps (such as MySQL’s » UNIX_TIMESTAMP function).

Timestamp of the start of the request is available in $_SERVER[‘REQUEST_TIME’] .

User Contributed Notes

Date/Time Functions
- checkdate
- date_add
- date_create_from_format
- date_create_immutable_from_format
- date_create_immutable
- date_create
- date_date_set
- date_default_timezone_get
- date_default_timezone_set
- date_diff
- date_format
- date_get_last_errors
- date_interval_create_from_date_string
- date_interval_format
- date_isodate_set
- date_modify
- date_offset_get
- date_parse_from_format
- date_parse
- date_sub
- date_sun_info
- date_sunrise
- date_sunset
- date_time_set
- date_timestamp_get
- date_timestamp_set
- date_timezone_get
- date_timezone_set
- date
- getdate
- gettimeofday
- gmdate
- gmmktime
- gmstrftime
- idate
- localtime
- microtime
- mktime
- strftime
- strptime
- strtotime
- time
- timezone_abbreviations_list
- timezone_identifiers_list
- timezone_location_get
- timezone_name_from_abbr
- timezone_name_get
- timezone_offset_get
- timezone_open
- timezone_transitions_get
- timezone_version_get
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