How to convert a column from hex string to long?

Question

I have a DataFrame with Icao column with hex codes that I would like to convert to Long datatype. How could I do this in Spark SQL?

Answer 1

You can use java hex to Long converter

java.lang.Long.parseLong(hex.trim(), 16)

All you need is to define a udf function as below

import org.apache.spark.sql.functions.udf
def hexToLong = udf((hex: String) => java.lang.Long.parseLong(hex.trim(), 16))

And call the udf function using .withColumn api

df.withColumn("Icao", hexToLong($"Icao")).show(false)

Answer 2

TL;DR Use conv standard function.

conv(num: Column, fromBase: Int, toBase: Int): Column Convert a number in a string column from one base to another.

With conv a solution could be as follows:

scala> icao.show
+------+-----+
|  Icao|count|
+------+-----+
|471F8D|81350|
|471F58|79634|
|471F56|79112|
|471F86|78177|
|471F8B|75300|
|47340D|75293|
|471F83|74864|
|471F57|73815|
|471F4A|72290|
|471F5F|72133|
|40612C|69676|
+------+-----+

// conv is not available by default unless you're in spark-shell
import org.apache.spark.sql.functions.conv

val s1 = icao.withColumn("conv", conv($"Icao", 16, 10))
scala> s1.show
+------+-----+-------+
|  Icao|count|   conv|
+------+-----+-------+
|471F8D|81350|4661133|
|471F58|79634|4661080|
|471F56|79112|4661078|
|471F86|78177|4661126|
|471F8B|75300|4661131|
|47340D|75293|4666381|
|471F83|74864|4661123|
|471F57|73815|4661079|
|471F4A|72290|4661066|
|471F5F|72133|4661087|
|40612C|69676|4219180|
+------+-----+-------+

conv has a feature of giving you a result of the type of the input column, so I started with strings and got strings.

scala> s1.printSchema
root
 |-- Icao: string (nullable = true)
 |-- count: string (nullable = true)
 |-- conv: string (nullable = true)

If I had used ints I'd have got ints.

You could cast the result of conv using another built-in method cast (or start with a proper type of the input column).

val s2 = icao.withColumn("conv", conv($"Icao", 16, 10) cast "long")
scala> s2.printSchema
root
 |-- Icao: string (nullable = true)
 |-- count: string (nullable = true)
 |-- conv: long (nullable = true)

scala> s2.show
+------+-----+-------+
|  Icao|count|   conv|
+------+-----+-------+
|471F8D|81350|4661133|
|471F58|79634|4661080|
|471F56|79112|4661078|
|471F86|78177|4661126|
|471F8B|75300|4661131|
|47340D|75293|4666381|
|471F83|74864|4661123|
|471F57|73815|4661079|
|471F4A|72290|4661066|
|471F5F|72133|4661087|
|40612C|69676|4219180|
+------+-----+-------+