SPARQL query and distinct count

If you’re using Java and Jena’s ARQ, you can use ARQ’s extensions for aggregates. Your query would look something like: SELECT ?tag (count(distinct ?tag) as ?count) WHERE { ?r ns9:taggedWithTag ?tagresource. ?tagresource ns9:name ?tag } LIMIT 5000 The original SPARQL specification from 2008 didn’t include aggregates, but the current version, 1.1, from 2013 does.

pyspark count rows on condition

count doesn’t sum Trues, it only counts the number of non null values. To count the True values, you need to convert the conditions to 1 / 0 and then sum: import pyspark.sql.functions as F cnt_cond = lambda cond: F.sum(F.when(cond, 1).otherwise(0)) test.groupBy(‘x’).agg( cnt_cond(F.col(‘y’) > 12453).alias(‘y_cnt’), cnt_cond(F.col(‘z’) > 230).alias(‘z_cnt’) ).show() +—+—–+—–+ | x|y_cnt|z_cnt| +—+—–+—–+ | bn| … Read more

Spark: How to translate count(distinct(value)) in Dataframe API’s

What you need is the DataFrame aggregation function countDistinct: import sqlContext.implicits._ import org.apache.spark.sql.functions._ case class Log(page: String, visitor: String) val logs = data.map(p => Log(p._1,p._2)) .toDF() val result = logs.select(“page”,”visitor”) .groupBy(‘page) .agg(‘page, countDistinct(‘visitor)) result.foreach(println)

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