Python bin() Function

The bin() function in Python converts an integer number into a binary string. This is helpful when you want to understand or manipulate numbers in binary format.

Syntax

bin(x)

Parameters:

• x – A non-complex integer number.

Returns:

• A string that starts with '0b' followed by the binary representation of the number.

Example 1: Convert Positive Integer to Binary

print(bin(10))

0b1010

Example 2: Convert Negative Integer to Binary

print(bin(-4))

-0b100

Use Case: Binary Representation for Bitwise Operations

a = 5
b = 3
print("Binary of a:", bin(a))
print("Binary of b:", bin(b))
print("a & b:", a & b)
print("Binary of (a & b):", bin(a & b))

Binary of a: 0b101
Binary of b: 0b11
a & b: 1
Binary of (a & b): 0b1

How to Get Binary Without '0b'

binary = bin(7)[2:]
print(binary)

111

Note: [2:] slices off the '0b' prefix.

Common Mistakes

• bin() only works on integers. If you pass a float, you'll get a TypeError.
• It does not pad with leading zeros. Use format() if you need fixed-length binary.

Interview Tip

Use bin() in coding interviews when dealing with bit manipulation problems, such as checking set bits, binary palindromes, or bitwise AND/OR operations.

Summary

• bin(x) converts an integer x into a binary string.
• The result always starts with '0b'.
• To remove '0b', slice the string using [2:].
• Only integer types are supported.

Practice Problem

Write a program that asks the user to enter an integer and then prints its binary form (without the '0b' prefix).

num = int(input("Enter an integer: "))
print("Binary representation:", bin(num)[2:])