How to get the newest file in a directory in php

问题:

So I have this app that processes CSV files. I have a line of code to load the file.

$myFile = "data/FrontlineSMS_Message_Export_20120721.csv";  //The name of the CSV file
$fh = fopen($myFile, 'r');                             //Open the file

I would like to find a way in which I could look in the data directory and get the newest file (they all have date tags so they would be in order inside of data) and set the name equal to $myFile.

I really couldn't find and understand the documentation of php directories so any helpful resources would be appreciated as well. Thank you.

回答1:

Here's an attempt using scandir, assuming the only files in the directory are the timestamped files you want:

$files = scandir('data', SCANDIR_SORT_DESCENDING);
$newest_file = $files[0];

We first list all files in the directory in descending order, then, whichever one is first in that list has the "greatest" filename — and therefore the greatest timestamp value — and is therefore the newest.

Note that scandir was added in PHP 5, but its documentation page shows how to implement that behavior in PHP 4.

回答2:

If your filenames don't have the timestamp in the name this question has already been answered here: PHP: Get the Latest File Addition in a Directory