Step by Step solution about How to resolve the algorithm Empty string step by step in the PHP programming language

1. empty() Function:

   • Checks if a variable is considered "empty". Empty values include:
     • Empty strings ('')
     • Null values (null)
     • Zero (0)
     • False (false)
     • Empty arrays ([])
     • Empty objects (new stdClass())

2. strlen() Function:

   • Returns the length of a string. An empty string has a length of 0.

3. Usage:

   • if (empty($str)): Checks if the $str variable is empty.
   • if (! empty($str)): Checks if the $str variable is not empty.
   • if ($str == ''): Same as empty($str) but compares the string to an empty string.
   • if ($str != ''): Same as ! empty($str) but compares the string to a non-empty string.
   • if (strlen($str) == 0): Checks if the length of the $str string is 0.
   • if (strlen($str) != 0): Checks if the length of the $str string is not 0.

4. Example:

   $str = '';
   if (empty($str)) {
    echo 'The $str variable is empty.';
   } else {
    echo 'The $str variable is not empty.';
   }

   Output:

   The $str variable is empty.
   

<?php

$str = ''; // assign an empty string to a variable

// check that a string is empty
if (empty($str)) { ... }

// check that a string is not empty
if (! empty($str)) { ... }

// we could also use the following
if ($str == '') { ... }
if ($str != '') { ... }

if (strlen($str) == 0) { ... }
if (strlen($str) != 0) { ... }