Use PHP glob() function to find files based on wildcard characters in file names

When processing files, we often encounter situations where we need to find a specified file. If the number of files is small, manual search can be used. However, if a large number of files are involved, manual search becomes overwhelming. At this time, a useful function comes in handy - the glob() function.

The glob() function is a very practical function in PHP, which allows us to find files and directories by specifying wildcard characters. The glob() function can also sort and filter the found files through various parameters, allowing us to quickly find the files we need among a large number of files.

Below, we start with the basic usage of the function and gradually introduce the use of the glob() function.

Basic usage of the glob() function

The glob() function is very simple. It has only one parameter - a wildcard character representing the file to be found. The following is an example:

$files = glob('/path/to/files/*.jpg');

The wildcard character in this example is "*.jpg", which means to search for all files with the suffix ".jpg" in the /path/to/files/ directory. The found results will be returned in the form of an array.

If we want to find all the files and subdirectories in a certain directory, we can use the "**" wildcard:

$files = glob('/path/to/files/**');

In this way, we can find the files in the /path/to/files/ directory All files and directories, including those under subdirectories.

In addition, we can also use square brackets in wildcards to specify a set of characters:

$files = glob('/path/to/files/[abc]*');

This way you can find all files starting with "a", "b" or "c" .

Advanced usage of the glob() function

The above introduces the basic usage of the glob() function. However, we can also set parameters to sort and filter the found results.

Set the sorting method

By setting the second parameter (indicating the sorting mode), we can sort the found results. The following are some commonly used sorting modes:

• GLOB_NOSORT: The default sorting mode, no sorting is performed.
• GLOB_NOCHECK: No error checking.
• GLOB_NOCASE: Not case sensitive.
• GLOB_BRACE: Enable brace expansion, you can use braces in wildcards.
• GLOB_ONLYDIR: Only search directories.
• GLOB_ERR: Stop the search if an error occurs.

For example, if we want to sort all files with the suffix ".jpg" in reverse order by name, we can use the following code:

$files = glob('/path/to/files/*.jpg', GLOB_NOSORT|GLOB_NOCHECK);
rsort($files);

In this example, we use two There are two constants GLOB_NOSORT and GLOB_NOCHECK to set the sorting method.

Set filter

By setting the third parameter (indicating the filter), we can filter the found results. Here are some commonly used filters:

• GLOB_MARK: Add "/" to the results to indicate a directory.
• GLOB_NOSORT: No sorting.
• GLOB_ONLYDIR: Only search directories.
• GLOB_ERR: Stop the search if an error occurs.
• GLOB_BRACE: Enable brace expansion, you can use braces in wildcards.
• GLOB_NOESCAPE: If turned on, "" in wildcard characters will not be escaped.
• GLOB_NOCHECK: No error checking.
• GLOB_NOCASE: File names are not case sensitive.

For example, if we only need to find files with a size of 100MB or less, we can use the following code:

$files = glob('/path/to/files/*.*');
array_filter($files, function($file) {
  return filesize($file) <= 100 * 1024 * 1024;
});

In this example, we use the array_filter() function to filter the results filter.

Summary

Through the above examples, we learned how to use the glob() function to search for files and directories in PHP. The glob() function is very simple and practical, and has many parameters and usages, which can achieve more complex and flexible file search and processing. In PHP projects, we can choose the glob() function to process large numbers of files and directories simply and efficiently.

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