PHP SplFileObject fseek() Function - Coding

The SplFileObject::fseek() function is an inbuilt function of Standard PHP Library (SPL) in PHP that allows you to move the file pointer to a specified position within a file opened using SplFileObject. The file pointer is the position where the next read or write operation will occur. This function is used to navigate within a file and read or write data from a specific location.

Syntax:

public SplFileObject::fseek(int $offset, int $whence = SEEK_SET): int

Parameters: This function accepts two parameters that are described below.

$offset: The offset value represents the number of bytes to move the file pointer. It can be positive or negative, depending on the direction you want to move the pointer.
$whence: This is an optional parameter that specifies the starting point for the offset calculation. It can take one of the following values: SEEK_SET – Set position equal to offset bytes, SEEK_CUR – Set position to current location plus offset, SEEK_END – Set position to end-of-file plus offset.

Program 1: The following program demonstrates the SplFileObject::fseek() function. Save this file name as “output.txt” before running this program.

Line 1: This is the first line of data.
Line 2: This is the second line of data.
Line 3: This is the third line of data.

PHP

<?php 
  
 $file = new SplFileObject('./output.txt', 'r'); 
   
// Move the file pointer to the 10th byte  
// from the beginning of the file. 
$file->fseek(10, SEEK_SET); 
  
// Read the content from the current position 
//(10th byte) to the end of the file. 
$content = $file->fread($file->getSize() - $file->ftell());  
echo $content; 
  
?>

Output:

is is the first line of data.
Line 2: This is the second line of data.
Line 3: This is the third line of data.

Program 2: The following program demonstrates the SplFileObject::fseek() function. Save this file name as “output.txt” before running this program.

Ram 
Seeta
Michael Johnson
Emily Brown
William Davis

PHP

<?php 
      
$file = new SplFileObject('output.txt', 'r'); 
  
// Move the file pointer to the beginning 
// of the third line (name) 
$file->fseek(strlen("Michael \n") * 2, SEEK_SET); 
     
// Read the third name from the current position. 
$thirdName = trim($file->fgets()); 
     
// Output the third name. 
echo "The third name in the file is: " . $thirdName;    
    
?>

Output:

The third name in the file is: Johnson

Reference: https://www.php.net/manual/en/splfileobject.fseek.php

Reffered: https://www.geeksforgeeks.org

PHP

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