Python Program to find First Digit of a Number

Write a Python Program to find First Digit of a Number using While Loop, pow, log10, and Functions with an example.

Python Program to find First Digit of a Number using While Loop

This Python program allows users to enter any integer value. Next, this program finds Factors of that number using a While Loop.

# Python Program to find First Digit of a Number

number = int(input("Please Enter any Number: "))

first_digit = number

while (first_digit >= 10):
    first_digit = first_digit // 10

print("The First Digit from a Given Number {0} = {1}".format(number, first_digit))

In this python program, number = 984. It means first_digit = 984

First Iteration of the While Loop
while (first_digit >= 10) – It means (984 >= 10) is True
first_digit = first_digit // 10
first_digit = 984 // 10 = 98

Second Iteration
while (98 >= 10)  – Condition is True
first_digit = 98 // 10 = 9

Third Iteration
while (9 >= 10)  – Condition is False. So, it exits from the While Loop, and print 9 as output

Python Program to find First Digit of a Number using Built-in Functions

In this Python program, we are using the building-in functions called math.pow and log10.

import math

number = int(input("Please Enter any Number: "))

count = int(math.log10(number))

first_digit = number // math.pow(10, count)

print("Total number of Digits in a Given Number {0} = {1}".format(number, count))
print("The First Digit from a Given Number {0} = {1}".format(number, first_digit))

Please Enter any Number: 67598
Total number of Digits in a Given Number 67598 = 4
The First Digit from a Given Number 67598 = 6.0

number = 67598

count = log10(number) – This will return 4.67
count = 4

first_digit = 67598 / pow(10, 4) = 67598 / 10000 = 6

Python Program to return First Digit of a Number using Functions

This first digit in a number program is the same as the first example. But this time, we separated the logic by defining a new function called first_digit.

def first_digit(number):
    while (number >= 10):
        number = number // 10
    return number

num = int(input("Please Enter any Number: "))

firstDigit = first_digit(num)

print("The First Digit from a Given Number {0} = {1}".format(num, firstDigit))

Please Enter any Number: 78543
The First Digit from a Given Number 78543 = 7