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PYSPARK • LESSON 215

Schema Validation & Cast Safety

How can we safely cast string numbers to integers and isolate corrupted alphanumeric strings?

Advanced3 Minutes840 XP
🤔 THE QUESTION

How can we safely cast string numbers to integers and isolate corrupted alphanumeric strings?

💡 WHAT IS IT?

Casting a non-numeric string to numeric produces null, which can be detected to separate valid rows from corrupted rows.

🎯 WHAT IS IT USED FOR?

Parsing unvalidated CSV columns into structured types with guaranteed cast safety.

💻 EXAMPLE
df_cast = df.withColumn("numeric_val", col("raw_val").cast("double"))
df_corrupted = df_cast.filter(col("raw_val").isNotNull() & col("numeric_val").isNull())

🎯 Mission Objectives

Practice typing production-grade PySpark code for Schema Validation & Cast Safety.

  • Safe type casting
  • Corrupted string detection
  • Schema compliance check