Github user HyukjinKwon commented on a diff in the pull request:
https://github.com/apache/spark/pull/16854#discussion_r104289988
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/DataFrameReader.scala ---
@@ -399,6 +395,52 @@ class DataFrameReader private[sql](sparkSession:
SparkSession) extends Logging {
}
/**
+ * Loads an `Dataset[String]` storing CSV rows and returns the result as
a `DataFrame`.
+ *
+ * Unless the schema is specified using `schema` function, this function
goes through the
+ * input once to determine the input schema.
+ *
+ * @param csvDataset input Dataset with one CSV row per record
+ * @since 2.2.0
+ */
+ def csv(csvDataset: Dataset[String]): DataFrame = {
+ val parsedOptions: CSVOptions = new CSVOptions(
+ extraOptions.toMap,
+ sparkSession.sessionState.conf.sessionLocalTimeZone)
+ val filteredLines = CSVUtils.filterCommentAndEmpty(csvDataset,
parsedOptions)
+ val maybeFirstLine = filteredLines.take(1).headOption
+ if (maybeFirstLine.isEmpty) {
+ return sparkSession.emptyDataFrame
--- End diff --
The reason why this one exists unlike json is, CSV needs to head a head
always first (even if it does not infer the schema, it needs at least the
number of values). In this case, we could return empty one fast.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org
