Which of the following code blocks returns a new DataFrame with a new column employeesPerSqft that is the quotient of column numberOfEmployees and column sqft, both of which are from DataFrame…

Question

Options

• AstoresDF.withColumn("employeesPerSqft", col("numberOfEmployees") / col("sqft"))
• BstoresDF.withColumn("employeesPerSqft", "numberOfEmployees" / "sqft")
• CstoresDF.select("employeesPerSqft", "numberOfEmployees" / "sqft")
• DstoresDF.select("employeesPerSqft", col("numberOfEmployees") / col("sqft"))
• EstoresDF.withColumn(col("employeesPerSqft"), col("numberOfEmployees") / col("sqft"))

• A
  90% (36)
• B
  5% (2)
• D
  3% (1)
• E
  3% (1)

Explanation

withColumn(name, expression) is the correct method to add or replace a column in a DataFrame. The first argument must be a string (the new column name), and the second must be a Column expression. Option A - storesDF.withColumn("employeesPerSqft", col("numberOfEmployees") / col("sqft")) - satisfies both requirements. Option B fails because Python string literals cannot be divided. Options C and D use select(), which doesn't add a column to an existing DataFrame the way described - it would require an alias and would drop all other columns. Option E passes a col() object as the first argument to withColumn, but that parameter must be a plain string.

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