Let's talk about how to use php to convert time into timestamp

In PHP programming, timestamp (timestamp) is a very common concept. Converting time to timestamp is a relatively simple operation. This article will introduce you how to use PHP to convert time into a timestamp.

1. What is a timestamp?

The timestamp refers to the number of seconds since "January 1, 1970 00:00:00" (Greenwich Mean Time). It is a representation of time, actually an integer data type, generally 10 or 13 bits. This representation is very convenient for calculating time intervals or comparing time sequences.

2. Timestamp conversion

1. Convert the current time to a timestamp

In PHP, you can use the time() function to get the current time stamp. This function has no parameters and can be called directly. As shown below:

$timestamp = time();
echo $timestamp;

This code will output the current timestamp, such as "1536188900".

2. Convert the specified time to a timestamp

If you want to convert the specified time to a timestamp, you can use the strtotime() function. The parameter of this function is a time string that needs to be converted into a timestamp. Time strings in various commonly used formats are supported. For example, the following code will convert the time string "2018-09-05 12:34:56" into a timestamp:

$time = "2018-09-05 12:34:56";
$timestamp = strtotime($time);
echo $timestamp;

The above code will output the timestamp "1536138896".

It should be noted that the strtotime() function can also handle relative time descriptions. For example, the following code can convert the string "next Monday" (next Monday) into a timestamp:

$time = "next Monday";
$timestamp = strtotime($time);
echo $timestamp;

3. Convert timestamp to date and time format

There is a date() function in PHP that can format timestamps into various date and time formats. The first parameter of the date() function is the date format string, and the second parameter is the timestamp that needs to be formatted (optional). For example, the following code will output "2018-09-05 12:34:56":

$timestamp = 1536138896;
$date = date("Y-m-d H:i:s", $timestamp);
echo $date;

It should be noted that the date() function can not only handle timestamps, but also other time formats.

3. Other important points and precautions

1. The timestamp is measured in seconds, so timestamps exceeding 10 digits will be stored as the maximum value of the integer variable.
2. On different servers, the time settings may be different. If you find that the timestamp is offset or wrong, you can use the date_default_timezone_set() function to change the server's default time zone.
3. PHP's default time zone is "UTC", which is Greenwich Mean Time. If you need to modify the time zone, you can use the date_default_timezone_set() function or modify it in the php.ini file.

Summary:

Through the introduction in this article, I believe you have mastered the method of converting time into a timestamp in PHP. This is a very practical technique and is often used in actual development. At the same time, we also need to pay attention to issues such as the data type and time zone of the timestamp to ensure time accuracy.

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