Explanation:
The dayofyear() function in Apache Spark is designed to work with Timestamp or Date types. The openDate column, being an integer representing UNIX epoch time (seconds since January 1, 1970), needs to be converted to a Timestamp type before dayofyear() can correctly extract the day of the year. Option A accurately points out this necessity. The other options either misunderstand the function's requirements or suggest incorrect methods for achieving the desired result.
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The following code block contains an error. It is intended to return a DataFrame with a column "dayOfYear" representing the day of the year (as an integer) derived from the "openDate" column in DataFrame "storesDF". Identify the error.
Note: The "openDate" column is of type integer and stores dates in UNIX epoch format (seconds since midnight on January 1, 1970).
Sample of storesDF:
| storeId | openDate |
|---|---|
| 0 | 1100746394 |
| 1 | 1474410343 |
| 2 | 1116610009 |
| 3 | 1180035265 |
| 4 | 1408024997 |
Code block:
storesDF.withColumn("dayOfYear", dayofyear(col("openDate")))
storesDF.withColumn("dayOfYear", dayofyear(col("openDate")))
A
The dayofyear() operation cannot extract the day of year from a column of type integer – column openDate must first be converted to type Timestamp.
B
The dayofyear() operation takes a quoted column name rather than a Column object as its first argument – the first argument should be "openDate".
C
The dayofyear() operation cannot extract the day of year from a column of type integer – column openDate must first be converted to type Date.
D
The dayofyear() operation is not applicable in a withColumn() call – the newColumn() operation must be used instead.
E
There is no dayofyear() operation – the day of year number must be extracted using substring utilities.