Databricks Exam Databricks-Certified-Associate-Developer-for-Apache-Spark-3.0 Topic 1 Question 5 Discussion

Actual exam question for Databricks's Databricks Certified Associate Developer for Apache Spark 3.0 exam

Question #: 5
Topic #: 1

[All Databricks Certified Associate Developer for Apache Spark 3.0 Questions]

Which of the following code blocks displays various aggregated statistics of all columns in DataFrame transactionsDf, including the standard deviation and minimum of values in each column?

AtransactionsDf.summary()

BtransactionsDf.agg('count', 'mean', 'stddev', '25%', '50%', '75%', 'min')

CtransactionsDf.summary('count', 'mean', 'stddev', '25%', '50%', '75%', 'max').show()

DtransactionsDf.agg('count', 'mean', 'stddev', '25%', '50%', '75%', 'min').show()

EtransactionsDf.summary().show()

Show Suggested Answer

Suggested Answer: E

The DataFrame.summary() command is very practical for quickly calculating statistics of a DataFrame. You need to call .show() to display the results of the calculation. By default, the command

calculates various statistics (see documentation linked below), including standard deviation and minimum. Note that the answer that lists many options in the summary() parentheses does not

include the minimum, which is asked for in the question.

Answer options that include agg() do not work here as shown, since DataFrame.agg() expects more complex, column-specific instructions on how to aggregate values.

More info:

- pyspark.sql.DataFrame.summary --- PySpark 3.1.2 documentation

- pyspark.sql.DataFrame.agg --- PySpark 3.1.2 documentation

Static notebook | Dynamic notebook: See test 3, Question: 46 (Databricks import instructions)

by Shonda at May 05, 2022, 05:00 PM

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