#Config_Method
The .option("nullValue") parameter in PySpark is used when reading data from external files like CSV, JSON, or similar formats to specify how certain values in the source data should be interpreted as NULL in the resulting DataFrame.

Syntax: -

df = spark.read.option("nullValue", "<value>").csv("<file_path>")

1. Custom Null Values: You can handle specific strings like "null", "N/A", "missing", etc., as nulls in your data.
2. Data Cleaning: Useful for preprocessing and cleaning datasets with inconsistent representations of missing values.
3. Applies to Supported Formats: Works with file formats like CSV, JSON, etc.