Which of the following operations can be used to return the number of rows in a DataFrame?

Question

Options

• ADataFrame.numberOfRows()
• BDataFrame.n()
• CDataFrame.sum()
• DDataFrame.count()
• EDataFrame.countDistinct()

• B
  2% (1)
• C
  7% (4)
• D
  89% (54)
• E
  3% (2)

Explanation

DataFrame.count() is the standard PySpark action that triggers a full scan of the DataFrame and returns the total number of rows as a Python integer. The other options do not exist or serve different purposes: numberOfRows() (A) and n() (B) are not PySpark DataFrame methods; sum() (C) aggregates numeric column values, not row counts; and countDistinct() (E) is a SQL function used inside aggregations to count distinct values in a column, not a top-level DataFrame method that counts rows.

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