I want to define a udf. In the function body, it will search data from external dataframe. How can I do that? I tried to pass the dataframe to udf. But it cannot work.
Sample code:
val countryDF = spark.read
.option("inferSchema", "true")
.option("header", "true")
.csv("Country.csv")
val geo = (originString: String, dataFrame: DataFrame) => {
// Search data from countryDF
val row = dataFrame.where(col("CountryName") === originString)
if (row != Nil){
// set data to row index 2
row.getAs[String](2)
}
else{
"0"
}
}
val udfGeo = udf(geo)
val cLatitudeAndLongitude = udfGeo(countryTestDF.col("CountryName"), lit(countryDF))
countryTestDF = countryTestDF.withColumn("Latitude", cLatitudeAndLongitude)
If you want to use a UDF, you have to work on columns, not on dataframe object You have to create a new column that take the output of the UDF.
def geo(originString : String, CountryName: String) : Int = {
if (CountryName == originString){
return 1}
else{
return 0}
}
val geoUDF = udf(geo _)
val newData = countryDF.withColum("isOrignOrNot", geoUDF(col("originString"),col("CountryName"))
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