logo
down
shadow

Convert arbitrary number of columns to Vector


Convert arbitrary number of columns to Vector

By : Yemen Ali
Date : November 18 2020, 03:01 PM
With these it helps This can be done in a simple way using VectorAssembler. The columns that are to be merged into a Vector are used as input, in this case all columns except the first.
code :
val df = spark.createDataFrame(Seq(("val1", 0, 1, 1), ("val2", 2, 1, 5)))
  .toDF("name", "a", "b", "c")

val columnNames = df.columns.drop(1) // drop the name column    
val assembler = new VectorAssembler()
  .setInputCols(columnNames)  
  .setOutputCol("values")

val df2 = assembler.transform(df).select("name", "values").as[ValuesRow]
+----+-------------+
|name|       values|
+----+-------------+
|val1|[0.0,1.0,1.0]|
|val2|[2.0,1.0,5.0]|
+----+-------------+


Share : facebook icon twitter icon
Convert dataframe columns to named number vector

Convert dataframe columns to named number vector


By : IntlMind
Date : March 29 2020, 07:55 AM
I wish this helpful for you I have a dataframe blah: , Just use setNames
code :
setNames(blah$y, blah$x)
# Red Blood Red   Crimson    Maroon 
#  20         1        14        13 
How to convert a vector into a matrix where values on columns are 1 where the column number is the vector element, else

How to convert a vector into a matrix where values on columns are 1 where the column number is the vector element, else


By : Shihan Shen
Date : March 29 2020, 07:55 AM
I hope this helps you . Your method is not efficient because you're growing the size of Y in the loop which is not a good programming practice. Here is how your code can be fixed:
code :
Ele = numel(y); 
Y= zeros(Ele, max(y));
for k = 1:Ele
    Y (k,y(k))= 1;
end
Ele = numel(y);          %Finding no. of elements in y
Y= zeros(Ele, max(y));   % Initiailizing the matrix of the required size with all zeros
lin_idx = sub2ind(size(Y), 1:Ele, y.'); % Finding linear indexes
Y(lin_idx)=1             % Storing 1 in those indexes
How can I convert an arbitrary number of columns in a Spark dataframe from Timestamps to Longs?

How can I convert an arbitrary number of columns in a Spark dataframe from Timestamps to Longs?


By : Benammar Ryane
Date : March 29 2020, 07:55 AM
wish of those help I'm writing this in Scala and am using Spark 1.6, and don't have the option to switch to a newer version. I'm attempting to merge two dataframes, one pulled in from Avro files on a Hadoop cluster and one pulled in from a Teradata db. I can read them both in just fine, and both are guaranteed to have the same column names in the same order, but when I try to merge them using , the following line is just transformation
code :
df.withColumn(fName, convert_timestamp_udf(df.col(fName)))
   def transformTimestamps(df: DataFrame): DataFrame = {
      val convert_timestamp_udf = udf((time:Timestamp) => time.getTime())
      var tempDF = df
      df.schema.map(f => {
        val fName = f.name
        val fType = f.dataType
        if (fType.toString == "TimestampType") {
          println("Found timestamp col: " + fName)
          tempDF = tempDF.withColumn(fName, convert_timestamp_udf(df.col(fName)))
          tempDF.printSchema()
        }
      })
      return tempDF
    }
How to shape array (sequence) to have arbitrary number of rows for a given number of columns

How to shape array (sequence) to have arbitrary number of rows for a given number of columns


By : Zeeshan
Date : March 29 2020, 07:55 AM
Hope this helps Let me know if any of the following code is unclear, as I will then elaborate on how it works.
Exact fit
Passing arbitrary number of parameters using vector in C++

Passing arbitrary number of parameters using vector in C++


By : Prophet
Date : March 29 2020, 07:55 AM
help you fix your problem I'm not sure what is wrong with pointers, but of course you can avoid pointers with reference_wrappers. (Don't forget to #include )
code :
void foo(const std::vector<std::reference_wrapper<integer>>& vec)
{
    for (auto it = vec.begin(); it != vec.end(); it++) {
        (*it)->increase();
    }
}
template <typename... Args>
void foo(Args&... args)
{
    static_assert(std::conjunction_v<std::is_same<Args, integer>...>);
    (args.increase(), ...);
}
Related Posts Related Posts :
  • Can spark-submit with named argument?
  • Scala alternative to series of if statements that append to a list?
  • Convert string column to Array
  • Unable to authenticate OAuth2 with Akka-Http
  • Iterate through rows in DataFrame and transform one to many
  • Spark Scala Delete rows in one RDD based on columns of another RDD
  • SPARK RDD Between logic using scala
  • Converting a Spark Dataframe to a mutable Map
  • Run a function in scala with a list as input
  • how to call a method from another method using scala?
  • Scala: Traversable foreach definition
  • How to handle multiple invalid query params in akka http?
  • Scala error: value $ is not a member of object org.apache.spark.api.java.JavaSparkContext
  • Extract a specific JSON structure from a json string in a Spark Rdd - Scala
  • Spark: How do I query an array in a column?
  • scala - Functional way to take a string and create a dictionary using specific delimiters
  • Spark Scala: convert arbitrary N columns into Map
  • How to delete file right after processing it with Play Framework
  • scala: mapping future of tuple
  • why does sameElements returns true for sets?
  • Scala: Class of Options to Option of Class
  • timeout in scala's future firstcompletedof
  • No 'scala-library*.jar' in every new IntelliJ Scala Project
  • What is the meaning of "new {}" in Scala?
  • Why I cannot use iterator again in Scala
  • Spark worker throws FileNotFoundException on temporary shuffle files
  • Version conflict: some are suspected to be binary incompatible
  • Sbt: when to use testQuick and how does it determine which tests to skip?
  • IntelliJ: Scala worksheet don't pick up code changes without restart
  • The relationship between Type Symbol and Mirror of Scala reflection
  • Difference between [ ] and ( ) to create new Scala objects
  • Error: Could not find or load main class Main Scala
  • Maximum value of an mllib Vector?
  • Scalafx: create lineChart in scala
  • Conversion to tuple with by-name parameter
  • How to convert RDD of JSONs to Dataframe?
  • Spark: display log messages
  • How to bind Slick dependency with Lagom?
  • Sorting numeric String in Spark Dataset
  • understanding unapply without case class
  • Parsing more than 22 fields with Spray Json without nesting case classes
  • Why is Scala returning a ';' expected but ',' found error?
  • Spark reading Avro file
  • How to refactor similar and repetitive functions in scala
  • Getting ClassCastException while trying to save file in avro format in spark
  • How to Microbenchmark using data from a file?
  • Overloaded method value trigger with alternatives for '=> Unit' parameter
  • Unselecting "Run worksheet in the compiler process" causes source file not to be found
  • Why adding two List[Map[String, Any]] changes the output result type to List[Equals] in scala?
  • shadow
    Privacy Policy - Terms - Contact Us © voile276.org