Think about your base case. For what inputs would it make sense to just write the answer directly into your program? 0? 1? Probably not anything more than that; you don't want a giant elif chain going up to "okay, if it's 314, we can just return '100111010'". Think about how many numbers you need to hardcode the answer for, as a sort of foundation for the recursion, and which ones you can and should have the algorithm handle.
Think about your recursive call. If you want to produce a binary representation of n, what call to dec2bin would get you most of the answer, so you could then modify the result a bit and return that? Well, if n is bigger than 1, the binary representation of n is the binary representation of n//2 with another digit stuck onto the end, just like the decimal representation of n is the decimal representation of n//10 with another digit on the end.
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Think about your base case. For what inputs would it make sense to just write the answer directly into your program? 0? 1? Probably not anything more than that; you don't want a giant elif chain going up to "okay, if it's 314, we can just return '100111010'". Think about how many numbers you need to hardcode the answer for, as a sort of foundation for the recursion, and which ones you can and should have the algorithm handle.
Think about your recursive call. If you want to produce a binary representation of n, what call to dec2bin would get you most of the answer, so you could then modify the result a bit and return that? Well, if n is bigger than 1, the binary representation of n is the binary representation of n//2 with another digit stuck onto the end, just like the decimal representation of n is the decimal representation of n//10 with another digit on the end.
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Your code was almost okay. You don't really have to maintain bStr. Suppose you know the binary representation of n//2 then binary representation of n is binary representation of n//2 and 0 if n is evenly divisible by 2 or 1.
Like for n = 3. n//2 = 1. dec2bin(n//2) = '01' so dec2bin(n) = '01'+'1'[because 3 is not evenly divisible by 2] = '011'
Your code should be this.
def dec2bin(n):
if n < 0:
return 'Must be a positive integer'
elif n == 0:
return '0'
else:
return dec2bin(n//2) + str(n%2)
That's all.
Programiz
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Python Program to Convert Decimal to Binary Using Recursion
To understand this example, you should have the knowledge of the following Python programming topics: ... Decimal number is converted into binary by dividing the number successively by 2 and printing the remainder in reverse order. # Function to print binary number using recursion def ...
A recursion function to convert decimal to binary [python]
To all following commenters: please, do not bring up the old circlejerk jokes/memes about recursion ("Understanding recursion...", "This is recursion...", etc.). We've all heard them n+2 too many times. I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns. More on reddit.com
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November 5, 2020Decimal to binary function in Python using recursion - Stack Overflow
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[Python] Using recursion to convert binary string to decimal integer
what is the specific issue you are having? looking through really quick it looks like you never have a base case of one digit. Another thing is when you convert binary to decimal you go right to left, which is correct in the way you are doing it (starting at the end of the string) but you are raising it to the wrong power. For example, if you have 100, which should be 4, you will be getting 2 with your logic in this line: return 2**len(n) + bintodec(n[:-1]) because it will do the else for the first two, then it will get to the 1, with it being the string "1", it will see that as a length of 1, instead of being 22. It is a little hard to explain when rushed, but you need to figure out a way to keep track of which binary digit you are on, unless you start from the front, which is another way to do it! More on reddit.com
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February 7, 2013Binary to decimal conversion (Recursive)
def bin(str): "Function outputs decimal representation of binary code inputed" if bin == "": return 0 else: So, a couple issues to start with. bin is the name of your function, but it is not an object, so checking to see if bin=="" won't be true. What you might be wanting to do is see if str == "" since str is the object you're operating on. [Recursive functions] ( http://en.m.wikipedia.org/wiki/Recursion_(computer_science) ) keep calling themselves until they're done. Your recursive function might process the first letter, then recall itself with the remaining letters and eventually end when there's nothing else to process (your base case!) and somehow add everything up More on reddit.com
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October 11, 2014Where can this decimal to binary recursion program be practiced in Python?
This program can be practiced with our Python compiler. It allows running and testing the recursive decimal to binary code instantly, making practice fast, easy, and efficient without any setup.
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Python Program to Convert Decimal to Binary using Recursion
Is recursion better than loops for decimal to binary conversion?
Recursion makes the code cleaner and easier to understand. However, for very large numbers, loops are more memory-efficient since recursion uses the call stack.
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Python Program to Convert Decimal to Binary using Recursion
How can I improve my recursion program for decimal to binary conversion?
You can add input validation, handle negative numbers separately, or store binary digits in a string for easier use in further calculations.
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Python Program to Convert Decimal to Binary using Recursion
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Python Program to Convert Decimal to Binary Using Recursion | Vultr Docs
December 6, 2024 - For numbers greater than or equal to 2, recursively divide the number by 2 and append the remainder to the results of recursive calls. ... def decimal_to_binary(n): if n < 2: return str(n) else: return decimal_to_binary(n // 2) + str(n % 2) ...
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Python Program to Convert Decimal to Binary Using Recursion | Basic , medium ,expert programs example in c,java,c/++
# Python program to convert decimal number into binary number using recursive function def binary(n): """Function to print binary number for the input decimal using recursion""" if n > 1: binary(n//2) print(n % 2,end = '') # Take decimal number from user dec = int(input("Enter an integer: ")) ...
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How to Convert Decimal to Binary Using Recursion in Python?
October 27, 2022 - # creating a function to convert ... == 0: # returning 0 if the number passed is 0 return 0 # Call the function recursively again by passing the given number by half result = getBinaryForm(decimalnum // 2) # Getting the last bit and multiply the result with 10 return decimalnum ...
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Convert Decimal to Binary Using Recursion | Python Program Tutorial - YouTube
In this video, learn Convert Decimal to Binary Using Recursion | Python Program Tutorial. Find all the videos of the 100+ Python Programs Course in this play...
Published August 13, 2022
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Python Program to Convert Decimal to Binary using Recursion
October 28, 2025 - Learn how to write a Python program to convert decimal to binary using recursion. Simplify the conversion process with this step-by-step guide.
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Python Program to Convert Decimal to Binary Using Recursion
November 8, 2021 - This process must be repeated till it becomes zero. We then write the remainder in reverse order. Therefore, by following these steps we will achieve 11111110 as the binary equivalent. To find out what 10101 is as a decimal, one must note that a binary number has only two numbers i.e.
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Python Program to Convert Decimal to Binary Using Recursion
In recursive function, we first divide the number with 2 and then again divide its quotient by 2. We continuously need to divide its quotient till we get the quotient as 1. At last, we reverse back all the remainders of the division process, ...
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How to Convert Decimal to Binary Using Recursion Using Python Codes? | Python Programs - YouTube
In this video, learn How to Convert Decimal to Binary Using Recursion Using Python Codes? | Python Programs. Find all the videos of the PYTHON PROGRAMMING Tu...
Published September 7, 2022 Views 442
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Python Decimal to Binary conversion using recursive function - YouTube
In this video you will learn how to use python to convert Decimal to Binary using recursive function
Published November 30, 2020 Views 427
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GeeksforGeeks
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Decimal to binary number using recursion - GeeksforGeeks
March 17, 2025 - The function recursively divides the decimal number by 2, appending the remainder as the next binary digit, constructing the binary representation from right to left.
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r/learnprogramming on Reddit: A recursion function to convert decimal to binary [python]
November 5, 2020 -
1.def decimalToBinary(n): 2. if n>1: 3. decimalToBinary(n//2) 4. print(n % 2, end = '') 5. 6.decimalToBinary(9)
I didn't understood, if there is a recursion then shouldn't the print function work only once?
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To all following commenters: please, do not bring up the old circlejerk jokes/memes about recursion ("Understanding recursion...", "This is recursion...", etc.). We've all heard them n+2 too many times. I am a bot, and this action was performed automatically. Please contact the moderators of this subreddit if you have any questions or concerns.
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if there is a recursion then shouldn't the print function work only once? No, that is the point of recursion. You keep traversing deeper and deeper into the call stack and when you have hit the base case you traverse back out executing the remaining code of each function. decimalToBinary(3) if n > 1 ---> true decimalToBinary(3//2) -> decimalToBinary(1) if n > 1 ----> false print (n % 2, end = '') -> print(1 % 2) -> print(1) print (n % 2, end = '') -> print(3 % 2) -> print(1) Result is: 11 It helps to think of recursive calls as of a staircase. With every recursion you move one floor up. When a recursive call ends, you need to go down that floor again until you reach the ground floor.
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Decimal to binary function in Python using recursion - Stack Overflow
I am new in Python and trying to write a binary-to-decimal converted function like below def decimaltobinary(n): if n > 1: decimaltobinary(n//2) print(n%2,end='') #return n%2
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Python Program to convert Decimal Number to Binary Number | Codez Up
March 13, 2021 - Otherwise, in the other part, we just print the Remainder for each call stack while doing recursion. def decimalToBinary(n): if n > 1: decimalToBinary(n//2) print(n % 2,end = '') Let’s create the main method which is going to ask for user ...
GeeksforGeeks
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Convert Decimal to Binary Number - GeeksforGeeks
The recursive function continues until the number is reduced to 1. This method is elegant but less efficient due to the function call stack. ... n = 17 # decimal number res = '' # binary result def dec_to_bin(n): if n > 1: # recursively divide the number dec_to_bin(n // 2) global res res += str(n % 2) # append the remainder (binary digit) dec_to_bin(n) print(res)
Published March 19, 2025
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Recursive Program for Binary to Decimal - GeeksforGeeks
July 11, 2025 - # Recursive Python3 program to ... - 0 # Add current tern and recur for # remaining terms return (((int(binary[i]) - 0) << (n - i - 1)) + toDecimal(binary, i + 1)) # Driver code if __name__ == "__main__" : binary = "1010" ...
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[FREE] Write a Python program to convert a decimal number to binary using recursion. - brainly.com
July 7, 2023 - To convert a decimal number to binary using recursion in Python, define a base case and use a recursive function that calls itself with the quotient of the number divided by 2. Concatenate the remainders to build the binary representation.