Python program for decimal to binary conversion

Decimal to binary conversion in Python

Here, in this page we will discuss the program for Decimal to binary conversion in python. A decimal number is a standard representation of integers or non-integers, decimal numbers are also called as numbers with base 10. Whereas in binary number system numbers are with base 10 and shows representation by 0 and 1.

Decimal to binary conversion

Methods discussed

  • Method 1: Binary Bits stored in Array
  • Method 2: Using mathematical operations to generate binary equivalent.

Algorithm  ( Method 1 )

  • Initialize a empty array as binaryArray
  • while input number is greater then 0
  • Append 1 if unit digit of num is odd else append 0
  • Assign half the value of num to num
  • Print all the values of  binaryArray

Python Code

Run
def convertBinary(num):
    binaryArray = []
    while num>0:
        binaryArray.append(num%2)
        num = num//2
    for j in binaryArray:
        print(j, end="")


decimal_num = 21
convertBinary(decimal_num)

Output

Binary of 21 is : 10101

Algorithm  ( Method 2 )

  • Initialize variables binary, i, rem and assign 0, 1, 0 respectively
  • While input number is greater then zero run he loop
  • rem equals to divisibility of input by 2
  • num equals to half of num
  • Add rem * i to binary
  • Multiply i by 10
  • return binary  

Python Code

Run
def convertBinary(num):
    binary = 0
    i, rem = 1, 0
    while num != 0:
        rem = num % 2
        num = num // 2
        binary += rem * i
        i *= 10
    return binary


decimal_num = 21
print("Binary of", decimal_num, "is : ", end="")
print(convertBinary(decimal_num))

Output

Binary of 21 is : 10101

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8 comments on “Python program for decimal to binary conversion”


  • priyarajswarnakar2018

    Follow this:-
    def decimaltoBinary(num):
    arr=[]
    while num>0:
    a=num%2
    arr.append(a)
    num=num//2

    arr=arr[::-1]
    for i in arr:
    print(i,end=””)

    num=int(input())
    decimaltoBinary(num)


  • Bharath

    without built in function:
    d=int(input())
    b=”
    i=0
    while(d!=0):
    r=d%2
    s=str(r)
    b+=s
    d=d//2
    i+=1
    print(b[::-1])


  • thedashinganon

    n = int(input(“Enter Decimal Number : “))
    res = 0
    i = 1
    while (n!=0):
    rem = n % 2
    res = res + rem * i
    n= n//2
    i = i*10
    pre = ‘0b’
    print(“Binary Value is “,(pre+str(res)))


  • Sonal

    num=int(input(“Enter the decimal number “))
    sum=0
    temp=num
    base=1
    while(temp):
    digit=temp%2
    sum+=digit*base
    base*=10
    temp//=2
    print(“The binary value of {} is {}”.format(num,sum))


  • Abhishek

    a=int(input(“Enter the number :”))
    c=[]
    def decimal(n):
    b=n%2
    d=n//2
    c.append(b)
    if(d==0):
    for i in c[::-1]:
    print(i,end=””)
    else:
    decimal(d)

    b=decimal(a)