Abhishek Gupta Abhishek Gupta -4 years ago 71
R Question

Not able to to convert R data frame to Spark DataFrame

When I try to convert my local dataframe in R to Spark DataFrame using:

raw.data <- as.DataFrame(sc,raw.data)

I get this error:

17/01/24 08:02:04 WARN RBackendHandler: cannot find matching method class org.apache.spark.sql.api.r.SQLUtils.getJavaSparkContext. Candidates are:
17/01/24 08:02:04 WARN RBackendHandler: getJavaSparkContext(class org.apache.spark.sql.SQLContext)
17/01/24 08:02:04 ERROR RBackendHandler: getJavaSparkContext on org.apache.spark.sql.api.r.SQLUtils failed
Error in invokeJava(isStatic = TRUE, className, methodName, ...) :

The question is similar to
sparkR on AWS: Unable to load native-hadoop library and

Answer Source

Don't need to use sc if you are using the latest version of Spark. I am using SparkR package having version 2.0.0 in RStudio. Please go through following code (that is used to connect R session with SparkR session):

if (nchar(Sys.getenv("SPARK_HOME")) < 1) {
Sys.setenv(SPARK_HOME = "path-to-spark home/spark-2.0.0-bin-hadoop2.7")
 library(SparkR, lib.loc = c(file.path(Sys.getenv("SPARK_HOME"), "R","lib")))
 sparkR.session(enableHiveSupport = FALSE,master = "spark://master url:7077", sparkConfig = list(spark.driver.memory = "2g"))

Following is the output of R console:

> data<-as.data.frame(iris)
> class(data)
[1] "data.frame"
> data.df<-as.DataFrame(data)
> class(data.df)
[1] "SparkDataFrame"
[1] "SparkR"
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