5 Best Ways to Convert Integer to Binary in Python

💡 Problem Formulation: Python developers often face the need to convert integers into their binary string representations. For instance, the integer 5 is represented by the binary string '101'. Converting integers to binary format is essential in various areas, including computing systems, cryptography, and data encoding tasks. This article explores straightforward and efficient methods to achieve this conversion.

Method 1: Using the Built-in bin() Function

The bin() function is Python’s built-in function designed specifically for converting an integer to its binary string equivalent. The output is a string prefixed with “0b” which indicates a binary literal.

Here’s an example:

number_to_convert = 123
binary_string = bin(number_to_convert)
print(binary_string)

Output:

'0b1111011'

This code snippet uses the built-in bin() function to convert the integer 123 into the binary string '0b1111011'. The prefix '0b' indicates that the number is in binary format.

Method 2: Using String Formatting

String formatting with the format specification mini-language allows you to convert an integer to a binary string straightforwardly. The 'b' format specifier indicates binary format.

Here’s an example:

number_to_convert = 123
binary_string = f"{number_to_convert:b}"
print(binary_string)

Output:

'1111011'

This snippet formats the integer 123 as a binary string without the “0b” prefix, using the new f-string syntax introduced in Python 3.6.

Method 3: Using Bitwise Operations

Bitwise operations can be used to manually convert an integer to a binary string. This approach provides a deeper understanding of how binary conversion works at a lower level.

Here’s an example:

number_to_convert = 123
binary_string = ''
while number_to_convert > 0:
    binary_string = str(number_to_convert % 2) + binary_string
    number_to_convert //= 2
print(binary_string)

Output:

'1111011'

The provided code uses a while loop to divide the integer by two repeatedly, appending the remainder to the start of the binary string until the number is zero.

Method 4: Using Recursion

Recursion provides an elegant approach to convert integers to binary by breaking the problem down into smaller, manageable parts until a base case is reached.

Here’s an example:

def int_to_binary(n):
    if n == 0:
        return '0'
    else:
        return int_to_binary(n // 2) + str(n % 2) if n > 1 else '1'

number_to_convert = 123
binary_string = int_to_binary(number_to_convert)
print(binary_string)

Output:

'1111011'

This recursive function continually divides the integer and concatenates the remainder until the base case of zero is reached, which constructs the binary string in reverse order.

Bonus One-Liner Method 5: Using List Comprehension and join()

A one-liner solution combines list comprehension and join() to convert integers to binary strings in a compact form.

Here’s an example:

number_to_convert = 123
binary_string = ''.join(str((number_to_convert >> i) & 1) for i in range(number_to_convert.bit_length() - 1, -1, -1))
print(binary_string)

Output:

'1111011'

This succinct one-liner shifts the integer right by each bit position, performs a bitwise AND with 1, converts each bit to a string, and then joins them together.

Summary/Discussion

• Method 1: bin() Function. Simplest and most direct way to convert integers to binary. Includes a ‘0b’ prefix indicating binary format. May not be suitable if the prefix needs to be omitted.
• Method 2: String Formatting. Uses Python’s formatting capabilities for a clear and concise conversion. Does not include the ‘0b’ prefix, making it favorable for use cases that require just the binary digits.
• Method 3: Bitwise Operations. Provides insight into the manual conversion process. More verbose and less efficient for large integers compared to other methods.
• Method 4: Recursion. Conceptually clean, but possibly less efficient due to stack overhead. Elegant for those with a strong grasp of recursion.
• Bonus Method 5: One-Liner with List Comprehension and join(). Compact, but may be less readable for those unfamiliar with list comprehensions or bitwise operations. Efficient and useful for code golfing.