Filter spark DataFrame on string contains

问题:

I am using Spark 1.3.0 and Spark Avro 1.0.0. I am working from the example on the repository page. This following code works well

val df = sqlContext.read.avro("src/test/resources/episodes.avro")
df.filter("doctor > 5").write.avro("/tmp/output")

But what if I needed to see if the doctor string contains a substring? Since we are writing our expression inside of a string. What do I do to do a "contains"?

回答1:

You can use contains (this works with an arbitrary sequence):

df.filter($"foo".contains("bar"))

like (SQL like with SQL simple regular expression whith _ matching an arbitrary character and % matching an arbitrary sequence):

df.filter($"foo".like("bar"))

or rlike (like with Java regular expressions):

df.filter($"foo".rlike("bar"))

depending on your requirements. LIKE and RLIKE should work with SQL expressions as well.

回答2:

In pyspark,SparkSql syntax:

where column_n like 'xyz%'

might not work.

Use:

where column_n RLIKE '^xyz' 

This works perfectly fine.