How to use Logarithm In PHP

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

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
Using Logarithm
Using str_split() Function

Tags:

#Geeks Premier League 2023 #Geeks Premier League #PHP #PHP Programs #Web Technologies

Using Loop

Using str_split() Function

How to use Logarithm In PHP

PHP

Find First and Last Digits of a Number in PHP

Similar Reads