Horje
Find First and Last Digits of a Number in PHP

Given a Number, the task is to find the first, and last digits of a number using PHP.

Examples:

Input: num = 145677
Output: First Digit: 1, and Last Digit: 7

Input: 101130
Output: First Digit: 1, and Last Digit: 0

There are three methods to get the first and last digit of number, these are:

 

Table of Content

Using Loop

In this section, we use while loop to get the first and last digit of number. Remainder operator is used to get the last digit of number, and for first digit, use while loop.

PHP

<?php
  
function firstAndLastDigits($number) {
    $lastDigit = $number % 10;
      
    while ($number >= 10) {
        $number = (int)($number / 10);
    }
      
    $firstDigit = $number;
      
    return [$firstDigit, $lastDigit];
}
  
$num = 12345;
list($firstDigit, $lastDigit) = firstAndLastDigits($num);
  
echo "First Digit: $firstDigit, Last Digit: $lastDigit";
  
?>

Output

First Digit: 1, Last Digit: 5

Using Logarithm

Here, we use Logarithm to get the first digit of number. To get the first digit, divide the number by 10 power length of given number i.e. $number / pow(10, $len).

Example:

PHP

<?php
  
function firstAndLastDigits($number) {
    $len = floor(log10($number));
    $firstDigit = (int)($number / pow(10, $len));
    $lastDigit = $number % 10;
    return [$firstDigit, $lastDigit];
}
  
$num = 12345;
list($firstDigit, $lastDigit) = firstAndLastDigits($num);
  
echo "First Digit: $firstDigit, Last Digit: $lastDigit";
  
?>

Output

First Digit: 1, Last Digit: 5

Using str_split() Function

In this section, first, we convert the number of string and then split into an array, then get the first and last element of array.

PHP

<?php
  
function firstAndLastDigits($number) {
    $arr = str_split((string)$number);
      
    $firstDigit = $arr[0];
    $lastDigit = $arr[sizeof($arr)-1];
    return [$firstDigit, $lastDigit];
}
  
$num = 12345;
list($firstDigit, $lastDigit) = firstAndLastDigits($num);
  
echo "First Digit: $firstDigit, Last Digit: $lastDigit";
  
?>

Output

First Digit: 1, Last Digit: 5




Reffered: https://www.geeksforgeeks.org

Geeks Premier League

Related
Postman vs Making HTTP Request and Asserting Response Postman vs Making HTTP Request and Asserting Response
Seventeenth Amendment Act, 1964 of Indian Constitution Seventeenth Amendment Act, 1964 of Indian Constitution
Importance of Software Testing in the Automotive Industry Importance of Software Testing in the Automotive Industry
Jira Agile Jira Agile
JIRA Waterfall Model JIRA Waterfall Model

Type:
 Geek
Category:
 Coding
Sub Category:
 Tutorial
Uploaded by:
 Admin
Views:
 11



 

Horje