pythonpyspark

How to concantenate elements of a binary column?


I have a DataFrame with a binary column that represents the hexadecimal encoding of an initial string:

random_id random_id_cesu8
123456789012 [31 32 33 34 35 36 37 38 39 30 31 32]

The random_id_cesu8 column contains the binary representation of the random_id string encoded in UTF-8 and displayed as a list of byte values in hexadecimal format.

I want to transform the random_id_cesu8 column into a single concatenated hexadecimal string: 313233343536373839303132, which is the concatenation of each individual byte value from the random_id_cesu8 list.

I’ve tried multiple approaches, but they all result in the original random_id value (123456789012) instead of the desired concatenated hexadecimal string (313233343536373839303132).

How can I correctly achieve this transformation?


Solution

  • Here's a solution using PySpark to convert the binary column to its hexadecimal representation:

    from pyspark.sql import functions as F
    
    # Create DataFrame with the initial value
    df = spark.createDataFrame([("123456789012",)], ["value"])
    
    # Convert the value to UTF-8 encoding and then to hex
    df = df.withColumn(
        "encoded_hex", 
        F.hex(F.encode(F.col("value"), 'utf-8')),
    )
    
    # Display the resulting DataFrame
    df.show(truncate=False)
    

    Explanation:

    1. encode(df.value, 'utf-8'): This function encodes the string value into a binary format using UTF-8 encoding.
    2. hex(): This function converts the binary data into its hexadecimal representation.

    The result will be a DataFrame with the encoded_hex column containing the desired hexadecimal string 313233343536373839303132.

    +------------+------------------------+
    |value       |encoded_hex             |
    +------------+------------------------+
    |123456789012|313233343536373839303132|
    +------------+------------------------+