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# bin() in Python

• Difficulty Level : Easy
• Last Updated : 01 Feb, 2018

Converting an decimal to binary is always an important utility that is required in python dev projects and competitive programming as well. Having a shorthand function to achieve this can always be handy in the situations which require the swift conversion of it without writing a long code for same, this is provided by “bin()“. This has been discussed in this article.

Naive Methods to convert decimal to binary

1. Using recursion

 `# Function to print binary number for the ``# input decimal using recursion``def` `decimalToBinary(n):`` ` `    ``if` `n > ``1``:``        ``# divide with integral result ``        ``# (discard remainder) ``        ``decimalToBinary(n``/``/``2``) `` ` ` ` `    ``print` `(n``%``2``,end``=``"")         `` ` `# Driver code``if` `__name__ ``=``=` `'__main__'``:``    ``decimalToBinary(``8``)``    ``print``(``"\r"``)``    ``decimalToBinary(``18``)``    ``print``(``"\r"``)``    ``decimalToBinary(``7``)``    ``print`

Output :

```1000
10010
111
```

2. Using loop

 `# Python code to demonstrate naive method``# using loop `` ` `# function returning binary string``def` `Binary(n):``    ``binary ``=` `""``    ``i ``=` `0``    ``while` `n > ``0` `and` `i<``=``8``:``        ``s1 ``=` `str``(``int``(n``%``2``))``        ``binary ``=` `binary ``+` `s1``        ``n ``/``=` `2``        ``i ``=` `i``+``1``        ``d ``=` `binary[::``-``1``]``    ``return` `d`` ` `print``(``"The binary representation of 100 (using loops) is : "``,end``=``"")``print``(Binary(``100``))`

Output:

```The binary representation of 100 (using loops) is : 001100100
```

Using bin()

Using bin() reduces the time required to code and also removes the hassle that you may see in the above two mentioned methods.

```Syntax :
bin(a)
Parameters :
a : an integer to convert
Return Value :
A binary string of an integer or int object.
Exceptions :
Raises TypeError when a float value is sent in arguments.
```
 `# Python code to demonstrate working of``# bin()`` ` `# function returning binary string``def` `Binary(n):``    ``s ``=` `bin``(n)``     ` `    ``# removing "0b" prefix``    ``s1 ``=` `s[``2``:]``    ``return` `s1`` ` `print``(``"The binary representation of 100 (using bin()) is : "``,end``=``"")``print``(Binary(``100``))`

Output :

```The binary representation of 100 (using bin()) is : 1100100
```

This article is contributed by Manjeet Singh. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.