Strip or Regex function in Spark 1.3 Dataframe

问题:

I have some code from PySpark 1.5 that I unfortunately have to port backwards to Spark 1.3. I have a column with elements that are alpha-numeric but I only want the digits. An example of the elements in 'old_col' of 'df' are:

 '125 Bytes'

In Spark 1.5 I was able to use

df.withColumn('new_col',F.regexp_replace('old_col','(\D+)','').cast("long"))

However, I cannot seem to come up with a solution using old 1.3 methods like SUBSTR or RLIKE. Reason being the number of digits in front of "Bytes" will vary in length, so what I really need is the 'replace' or 'strip' functionality I can't find in Spark 1.3 Any suggestions?

回答1:

As long as you use HiveContext you can execute corresponding Hive UDFs either with selectExpr:

df.selectExpr("regexp_extract(old_col,'([0-9]+)', 1)")

or with plain SQL:

df.registerTempTable("df")
sqlContext.sql("SELECT regexp_extract(old_col,'([0-9]+)', 1) FROM df")