PHP Set Timezone

Setting the timezone in PHP can be achieved in a few different ways. Here are a few common methods:

1. Using the date_default_timezone_set() function:

The date_default_timezone_set() function is used to set the default timezone used by all date/time functions in a script.

Here's an example of how to use it:

<?php
date_default_timezone_set('America/New_York');

echo 'The current date/time in New York is: ' . date('Y-m-d H:i:s');
?>

In the above script, 'America/New_York' is the timezone being set, and date('Y-m-d H:i:s') outputs the current date and time in the 'Y-m-d H:i:s' format.

You can replace 'America/New_York' with any valid timezone identifier from this list: https://www.php.net/manual/en/timezones.php.

2. Using the ini_set() function:

The ini_set() function is used to set configuration options for a PHP script. You can use it to set the date.timezone configuration option, which is the default timezone used by all date/time functions.

Here's an example of how to use it:

<?php
ini_set('date.timezone', 'Europe/London');

echo 'The current date/time in London is: ' . date('Y-m-d H:i:s');
?>

In the above script, 'Europe/London' is the timezone being set.

3. Setting the timezone in the php.ini file:

You can also set the default timezone directly in the php.ini configuration file, which is the main configuration file for PHP. Find the line that says ;date.timezone =, uncomment it by removing the semicolon at the start, and set it to your desired timezone:

date.timezone = "Asia/Kolkata"

After you make this change, you'll need to restart your web server for the changes to take effect. Note that this will set the default timezone for all PHP scripts, not just a single script.

PHP date_default_timezone_set() example:
- Set the default timezone for date and time functions using date_default_timezone_set().
```
// File: set_timezone.php
date_default_timezone_set('America/New_York');

// Perform operations with adjusted timezone
```

List of supported timezones in PHP:

Refer to the official PHP documentation for a comprehensive list of supported timezones.

// File: list_timezones.php
$timezones = timezone_identifiers_list();

// Output the list of timezones
print_r($timezones);

Set default timezone in PHP globally:
- Configure the default timezone globally for the entire PHP environment.
```
// File: php.ini
date.timezone = "America/New_York"
```

PHP set timezone for date and time functions:

Adjust the timezone specifically for date and time functions.

// File: specific_timezone.php
$date = new DateTime('now', new DateTimeZone('Europe/London'));

// Perform operations with the specified timezone

How to convert timezones in PHP:

Use DateTime and DateTimeZone objects to convert between different timezones.

// File: convert_timezone.php
$date = new DateTime('2023-01-01 12:00:00', new DateTimeZone('America/New_York'));
$date->setTimezone(new DateTimeZone('Europe/London'));

// Perform operations with the converted timezone

PHP timezone offset calculation:

Calculate the timezone offset for a specific timezone.

// File: timezone_offset.php
$timezone = new DateTimeZone('America/New_York');
$offset = $timezone->getOffset(new DateTime('now'));

echo "Timezone offset: " . ($offset / 3600) . " hours";

Set timezone in PHP.ini file:
- Update the php.ini file to set the default timezone for the entire PHP environment.
```
; File: php.ini
date.timezone = "America/New_York"
```