PHP function introduction—filemtime(): Get the last modification time of a file

PHP function introduction—filemtime(): Get the last modification time of a file

Overview:
In PHP, filemtime() is a very commonly used function, used to get the last modification time of a file . Through this function, we can get the last modification timestamp of the file to facilitate the operation and processing of the file. This article will introduce how to use the filemtime() function and provide code examples to help readers better understand and use this function.

Function syntax:
int filemtime (string $filename)

Parameter description:

• $filename: The file name or file whose last modification time is to be obtained path. Can be a relative path or an absolute path.

Return value:

• If the file exists, the timestamp of the last modification time of the file is returned;
• If the file does not exist or cannot be read , returns false.

Code example:
$file = './test.txt'; // Set the file path to get the last modification time

if (file_exists($file)) { // Confirm whether the file exists

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}
?>

Function analysis:
The above code first uses a relative path "./test.txt" to indicate that we want to get the file with the last modification time. You can change it to the appropriate file path according to your needs.
Next, we used the file_exists() function to check whether the file exists to avoid calling the filemtime() function when the file does not exist and causing an error. If the file exists, we use the filemtime() function to get the last modification time of the file and save it in the $lastModifiedTime variable.
Finally, we use the date() function to format the timestamp in the form of "Y-m-d H:i:s", and print out the last modification time of the file through the echo statement.

Note:

• Before using the filemtime() function, it is recommended to use the file_exists() function to confirm whether the file exists to avoid errors when calling the function.
• The timestamp returned by the function is an integer value, which needs to be converted into a more readable date and time format using the date() function.

Summary:
The filemtime() function is an important function in PHP for obtaining the last modification time of a file. By using this function, we can easily get the last modification time of the file, so that we can better process and operate the file. When using this function, we must pay attention to confirm whether the file exists to avoid errors when calling the function. I hope that the introduction and sample code of this article can help readers better understand and use the filemtime() function.

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