PHP file(): Read a file into an array by lines

The PHP file() function is used when we need to get the whole content of a file as an array. For example:

<?php
   $x = file("codescracker.txt");
   print_r($x);
?>

The output of the above PHP example on the file() function is:

That is, the file() function reads a file into an array, where each line of the file becomes an element of the array. And since there are three lines, the file codescracker.txt contains them; therefore, we have seen the above output.

Also, if we write:

echo $x[0];

Or,

print_r($x[0]);

We will get the same output using both of the above statements; that will be the first line of the file. For example:

<?php
   $x = file("codescracker.txt");
   echo $x[0];
   echo "<br>";
   echo $x[1];
   echo "<br>";
   echo $x[2];
?>

Now the output of the above PHP example is:

PHP file() Syntax

The syntax of the file() function in PHP is:

file(filename, flag, context)

The first parameter (filename) is required, whereas the last two (flag and context) parameters are optional.

Note: The filename parameter is used to specify the name of a file along with its extension, available in the current directory (the directory where the PHP code to read the file using file() is saved).

Note: The flag parameter is used to specify the flag value using:

• FILE_USE_INCLUDE_PATH: Used when we need to search the file in the include_path (in PHP.ini).
• FILE_IGNORE_NEW_LINES: Used when we need to omit the newline at the end of each element.
• FILE_SKIP_EMPTY_LINES: Used when we need to omit empty lines.

Note: The context is used when we need to specify the resource of the context stream.

Advantages of the file() function in PHP

• The file() function reads a file in one line of code.
• The file() function reads each file line without a loop.
• The file() function supports text, CSV, and XML files.
• PHP array functions make file manipulation easy since the function returns an array.

Disadvantages of the file() function in PHP

• For large files, the file() function reads the entire file into an array, which uses a lot of memory. This can slow or crash the script.
• If the user controls the file being read, the file() function can be dangerous. Malicious users can access sensitive server files.
• The file() function cannot skip lines or read specific file sections.
• The file() function does not provide detailed error messages if the file cannot be read, making file reading issues difficult to troubleshoot.

PHP Online Test