π‘ Problem Formulation: In Python, developers might encounter a situation where they need to convert a list of strings into binary data. Suppose you have a list of words ['hello', 'world'] and the goal is to obtain a list of corresponding binary representations like ['01101000 01100101 01101100 01101100 01101111', '01110111 01101111 01110010 01101100 01100100']. This can be useful for encoding text for various binary-based computation or communication purposes.
Method 1: Using the ord() Function and Format
This method involves iterating over each string in the list and then each character within those strings to convert them to their ASCII value using ord(), and then formatting those values to binary using format().
Here’s an example:
strings = ['hello', 'world']
binary_list = []
for string in strings:
binary_string = ' '.join(format(ord(char), 'b') for char in string)
binary_list.append(binary_string)
print(binary_list)Output:
['1101000 1100101 1101100 1101100 1101111', '1110111 1101111 1110010 1101100 1100100']
This code snippet creates an empty list binary_list. It then iterates over the list of strings and within that loop, iterates over each character in each string, converts them to their ASCII value using ord(), converts that to a binary string using format() with ‘b’ as format specification for binary, joins the binary strings with spaces, and then appends the result to binary_list.
Method 2: Using the bin() Function with List Comprehensions
The bin() function returns a binary string prefixed with “0b”. We can use list comprehensions for a concise way of converting the entire list of strings to a list of binary strings, slicing off the “0b” prefix.
Here’s an example:
strings = ['foo', 'bar'] binary_list = [' '.join(bin(ord(c))[2:].zfill(8) for c in word) for word in strings] print(binary_list)
Output:
['01100110 01101111 01101111', '01100010 01100001 01110010']
In this example, the list comprehension iterates over each string and character, converting characters to binary using the bin() method. The “0b” prefix is removed by slicing, and zfill(8) is used to ensure each byte has a full 8 bits.
Method 3: Using Bitwise Operations
To convert strings to binary without using built-in string format functions, we can employ bitwise operations. This involves shifting bits and using bitwise AND to extract binary digits.
Here’s an example:
strings = ['abc', 'xyz']
binary_list = []
for s in strings:
binary_string = ''
for char in s:
binary_string += ' '.join(str((ord(char)>>i)&1) for i in range(8))[::-1]
binary_list.append(binary_string)
print(binary_list)Output:
['01100001 01100010 01100011', '01111000 01111001 01111010']
This method manually computes the binary string for each character by bitwise shifting and AND-ing values. The range(8) indicates an 8-bit representation for each character. The resulting binary digits are reversed to match the correct order.
Method 4: Using the encode() Method and hexlify()
To handle non-ASCII characters, we can encode strings using UTF-8 and then translate the result into binary using the binascii module’s hexlify() function.
Here’s an example:
import binascii
strings = ['γγγ«γ‘γ―', 'δΈη']
binary_list = []
for s in strings:
encoded_string = s.encode('utf-8')
hex_representation = binascii.hexlify(encoded_string)
binary_string = ' '.join(bin(int(hex_representation[i:i+2], 16))[2:].zfill(8) for i in range(0, len(hex_representation), 2))
binary_list.append(binary_string)
print(binary_list)Output:
['11101001 10001101 10101000 11101001 10001100 10111101 11101001 10001100 10111010', '11100101 10000000 10111101 11101001 10001100 10000000']
This example uses the encode() method to convert the string to bytes, then uses the hexlify() function to obtain the hexadecimal representation. It then converts each hex pair to binary, padding each byte to 8 bits.
Bonus One-Liner Method 5: Using Int and Bytearray
For a concise one-liner conversion, we can use the int function with a bytearray, converting the entire string directly to binary, assuming it’s encoded in UTF-8.
Here’s an example:
strings = ['hi', 'bye'] binary_list = [' '.join(format(byte, '08b') for byte in bytearray(s, 'utf8')) for s in strings] print(binary_list)
Output:
['01101000 01101001', '01100010 01111001 01100101']
This one-liner uses a list comprehension to create a bytearray for each string, then formats each byte into its binary representation, ensuring each is 8 bits with leading zeros if necessary.
Summary/Discussion
- Method 1: Using the ord() and format functions. Strengths: straightforward implementation, suitable for ASCII strings. Weaknesses: verbose and may not handle extended Unicode characters properly.
- Method 2: Using the bin() function with list comprehensions. Strengths: concise and easy to read. Weaknesses: still limited to ASCII unless combined with utf-8 encoding.
- Method 3: Using bitwise operations. Strengths: educates on lower-level bit manipulation, avoids built-in string functions. Weaknesses: somewhat complex and less readable.
- Method 4: Using the encode() method and hexlify(). Strengths: handles UTF-8 encoding, thus supporting a larger character set. Weaknesses: requires importing an additional module and is relatively complex.
- Method 5: The one-liner using int and bytearray. Strengths: succinct and elegant. Weaknesses: may be less readable for novice programmers, and the use of utf-8 needs to be made explicit if dealing with non-ASCII characters.