Which of the following code blocks returns a DataFrame containing a column dayOfYear, an integer representation of the day of the year from column openDate from DataFrame storesDF?
Note that column openDate is of type integer and represents a date in the UNIX epoch format – the number of seconds since midnight on January 1st, 1970.
A sample of storesDF is displayed below:
To return a DataFrame containing a column dayOfYear, which is an integer representation of the day of the year from the column openDate, the openDate must first be cast to a timestamp because the dayofyear function works with timestamp data types. The correct code block is (storesDF.withColumn("openTimestamp", col("openDate").cast("Timestamp")).withColumn("dayOfYear", dayofyear(col("openTimestamp")). This ensures that the openDate is correctly interpreted as a date and time, allowing the dayofyear function to extract the correct day of the year.
storesDF.withColumn("openTimestamp", col("openDate").cast("Timestamp")).withColumn("dayOfYear", dayofyear(col("openTimestamp")))
The answer should be A. Unixtime should be cast to timestamp first
A is correct: from pyspark.sql.functions import col, dayofyear storesDF = spark.createDataFrame([(0, 1100746394), (1, 1474410343)], ['storeId', 'openDate']) storesDF = (storesDF.withColumn("openTimestamp", col("openDate").cast("Timestamp")).withColumn("dayOfYear", dayofyear(col("openTimestamp")))) display(storesDF)
A is correct
A. dayofyear function in PySpark's functions module expects the column openDate to be of type timestamp rather than long.
The correct answer is C. Option A is correct because it casts the openDate column to a timestamp using cast("Timestamp") and then uses the dayofyear function to extract the day of the year from the timestamp. Option B is incorrect because it contains syntax errors, including the "get" keyword, which is not necessary or valid in this context. Option C is close, but it does not cast the openDate column to a timestamp, which is necessary to use the dayofyear function. Option D is incorrect because it converts column "openDate" to a date format, which is unnecessary for extracting the day of the year. Additionally, the dayofyear() function can be applied directly to the "openDate" column. Option E is incorrect because it uses the substr() function to extract a substring from the "openDate" column, which does not correspond to the day of the year.