PHP - Ds Sequence::set() Function

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The PHPDs\Sequence::set()function is used to update a value at the given index. The index is the position of the element in sequence starting at 0, representing the first element, 1 representing the second element, and so on.

If the specified index is invalid (i.e., negative or greater than the sequence size), this function will throw an "OutOfRangeException".

Syntax

Following is the syntax of the PHP Ds\Sequence::set() function −

public abstract void Ds\Sequence::set( int $index , mixed $value )

Parameters

Following are the parameters of this function −

• index − The 0th-based index of the value to update.
• value − The new value replaced to.

Return value

This function does not return any value.

Example 1

The following program demonstrates the usage of the PHP Ds\Sequence::set() function −

<?php
   $seq = new \Ds\Vector([10, 20, 30, 40, 50]);
   echo "The sequence elements are: \n";
   print_r($seq);
   echo "The updated sequence is: \n";
   #using set() function
   $seq->set(1, 100);
   print_r($seq);
?>

Output

Following is the output of the above program −

The sequence elements are:
Ds\Vector Object
(
    [0] => 10
    [1] => 20
    [2] => 30
    [3] => 40
    [4] => 50
)
The updated sequence is:
Ds\Vector Object
(
    [0] => 10
    [1] => 100
    [2] => 30
    [3] => 40
    [4] => 50
)

Example 2

The following is another example of the PHP Ds\Sequence::set() function. We use this function to update the existing value with "Hyderabad" at index 2 in this sequence (["Tutorials", "Point", "India"]) −

<?php
   $seq = new \Ds\Vector(["Tutorials", "Point", "India"]);
   echo "The original sequence: \n";
   print_r($seq);
   $index = 2;
   $val = "Hyderabad";
   echo "The given index is: ".$index;
   echo "\nThe given value is: ".$val;
   echo "\nThe updated sequence: \n";
   #using set() function
   $seq->set($index, $val);
   print_r($seq);
?>

Output

The above program produces the following output −

The original sequence:
Ds\Vector Object
(
    [0] => Tutorials
    [1] => Point
    [2] => India
)
The given index is: 2
The given value is: Hyderabad
The updated sequence:
Ds\Vector Object
(
    [0] => Tutorials
    [1] => Point
    [2] => Hyderabad
)

Example 3

If the specified index is invalid (i.e., negative), the set() function will throw an "OutOfRangeException" −

<?php
   $seq = new \Ds\Vector(['a', 'e', 'i', 'o', 'u']);
   echo "The original sequence: \n";
   print_r($seq);
   $index = -1;
   $val = 'A';
   echo "The given index is: ".$index;
   echo "\nThe given value is: ".$val;
   echo "\nThe updated sequence: \n";
   #using set() function
   $seq->set($index, $val);
   print_r($seq);
?>

Output

After executing the above program, the following will be displayed −

The original sequence:
Ds\Vector Object
(
    [0] => a
    [1] => e
    [2] => i
    [3] => o
    [4] => u
)
The given index is: -1
The given value is: A
The updated sequence:
PHP Fatal error:  Uncaught OutOfRangeException: 
Index out of range: -1, expected 0 <= x <= 4 in C:\Apache24\htdocs\index.php:11
Stack trace:
#0 C:\Apache24\htdocs\index.php(11): Ds\Vector->set(-1, 'A')
#1 {main}
  thrown in C:\Apache24\htdocs\index.php on line 11